Cardiomyopathy of unknown origin. Cardiomyopathy. Rheumatological pathology or connective tissue diseases
Hypertrophic cardiomyopathy (HCM) is the most common cardiomyopathy. This is a genetically determined heart disease characterized by significant hypertrophy of the left ventricular myocardium equal to or greater than 15 mm according to cardiac ultrasound. At the same time, there are no diseases of the cardiovascular system that can cause such pronounced myocardial hypertrophy (AH, aortic heart disease, etc.).
HCM is characterized by the preservation of the contractile function of the left ventricular myocardium (often even its increase), the absence of expansion of its cavity and the presence of a pronounced violation of the diastolic function of the left ventricular myocardium.
Myocardial hypertrophy can be symmetrical (increase in wall thickness of the entire left ventricle) or asymmetric (increase in wall thickness alone). In some cases, only isolated hypertrophy of the upper part of the interventricular septum is observed directly under the annulus of the aortic valve.
Depending on the presence or absence of a pressure gradient in the outflow tract of the left ventricle, obstructive (narrowing the outflow part of the left ventricle) and non-obstructive HCM are distinguished. Obstruction of the outflow tract can be localized both under the aortic valve (subaortic obstruction) and at the level of the middle of the cavity of the left ventricle.
The incidence of HCM in the population is 1\500 people, more often in young age; the average age of patients at the time of diagnosis is about 30 years. However, the disease can be detected much later - at the age of 50-60 years; in isolated cases, HCM is detected in people over 70 years of age, which is casuistry. Late detection of the disease is associated with mild severity of myocardial hypertrophy and the absence of significant changes in intracardiac hemodynamics. Coronary atherosclerosis occurs in 15-25% of patients.
Etiology
HCM is a genetically determined disease transmitted in an autosomal dominant manner. HCM is caused by a mutation in one of 10 genes, each of which encodes certain protein structures of sarcomeres, consisting of thin and thick filaments, which have contractile, structural and regulatory functions. Most often, HCM is caused by mutations in 3 genes encoding beta-myosin heavy chains (gene located on chromosome 14), cardiac troponin C (gene located on chromosome 1) and myosin-binding protein C (gene located on chromosome 11). Mutations in 7 other genes responsible for regulatory and essential light chain myosin, titin, α-tropomyosin, α-actin, cardiac troponin I and α-myosin heavy chains are much less common.
It should be noted that there are no direct parallels between the nature of the mutation and the clinical (phenotypic) manifestations of HCM. Not all individuals with these mutations will have clinical manifestations of HCM, as well as signs of myocardial hypertrophy on the ECG and according to ultrasound of the heart. At the same time, it is known that the survival rate of patients with HCM resulting from a mutation in the beta-myosin heavy chain gene is significantly lower than with a mutation in the troponin T gene (in this situation, the disease manifests itself at a later age).
Nevertheless, the probands of a patient with HCM should be informed about the hereditary nature of the disease and about the autosomal dominant principle of its transmission. Moreover, first-line relatives should be carefully evaluated clinically using ECG and cardiac ultrasound.
The most accurate method for confirming HCM is DNA analysis, which allows you to directly identify mutations in genes. However, at present, due to the complexity and high cost of this technique, it has not yet received wide distribution.
Pathogenesis
In HCM, 2 main pathological mechanisms are noted - a violation of the diastolic function of the heart and, in some patients, obstruction of the outflow tract of the left ventricle. During diastole, the ventricles, due to their poor compliance, receive an insufficient amount of blood, which leads to a rapid rise in end-diastolic pressure. Under these conditions, hyperfunction, hypertrophy, and then dilatation of the left atrium develop compensatory, and with its decompensation, pulmonary hypertension (“passive” type) develops.
Left ventricular outflow obstruction that develops during ventricular systole is due to two factors: thickening of the interventricular septum (myocardial) and impaired movement of the anterior mitral valve leaflet. The papillary muscle is shortened, the valve leaflet is thickened and covers the outflow of blood from the left ventricle due to paradoxical movement: during the period of systole, it approaches the interventricular septum and comes into contact with it. That is why subaortic obstruction is often combined with mitral regurgitation, i.e. with mitral valve insufficiency. Due to left ventricular obstruction during ventricular systole, a pressure gradient develops between the left ventricular cavity and the ascending aorta.
From a pathophysiological and prognostic point of view, a resting pressure gradient greater than 30 mm Hg is significant. In some patients with HCM, the pressure gradient may increase only during exercise, and at rest be normal. In other patients, the pressure gradient is constantly elevated, including at rest, which is less favorable prognostically. Depending on the nature and degree of increase in the pressure gradient, patients with HCM are divided into:
Patients with persistent obstruction of the outlet section, in whom the pressure gradient constantly, including at rest, exceeds 30 mm Hg. (2.7 m/s on Doppler ultrasound);
Patients with latent obstruction of the outlet section, in whom the pressure gradient is less than 30 mm Hg at rest, and during provocative tests with physical (treadmiltest, bicycle ergometry) or pharmacological (dobutamine) load, the pressure gradient exceeds 30 mm Hg. ;
Patients without obstruction of the outlet section, in whom the pressure gradient does not exceed 30 mm Hg both at rest and during provocative tests with physical or pharmacological stress.
It should be taken into account that the pressure gradient in the same patient can vary widely depending on various physiological conditions (rest, exercise, food intake, alcohol, etc.).
The constantly existing pressure gradient leads to excessive tension of the left ventricular myocardium, the occurrence of its ischemia, the death of cardiomyocytes and their replacement with fibrous tissue. As a result, in addition to pronounced disorders of diastolic function due to rigidity of the hypertrophied left ventricular myocardium, systolic dysfunction of the left ventricular myocardium develops, which ultimately leads to chronic heart failure.
Clinical picture
For HCM, the following variants of the clinical course are characteristic:
Stable condition of patients for a long time, while about 25% of patients with HCM have a normal life expectancy;
Sudden cardiac death due to fatal ventricular arrhythmias (ventricular tachycardia, ventricular fibrillation), the risk of which in patients with HCM is quite high;
Progression of the clinical manifestations of the disease with preserved systolic function of the left ventricle: shortness of breath during physical exertion, pain in the heart of an anginal or atypical nature, impaired consciousness (fainting, pre-syncope, dizziness);
The emergence and progression of chronic heart failure up to the terminal (IV functional class according to NYHA) stage, accompanied by systolic dysfunction and remodeling of the left ventricle of the heart;
The occurrence of atrial fibrillation and its characteristic complications (ischemic stroke and other systemic thromboembolism);
The occurrence of IE, which complicates the course of HCM in 5-9% of patients (in this case, an atypical course of IE is characteristic with more frequent damage to the mitral valve than to the aortic valve).
Patients with HCM are characterized by an extreme variety of symptoms, which leads to misdiagnosis. Often they are diagnosed with rheumatic heart disease and coronary artery disease as a result of the similarity of complaints (pain in the heart and behind the sternum) and study data (intense systolic murmur).
In typical cases clinical picture are:
Complaints of shortness of breath during physical exertion and a decrease in tolerance to them, pain in the heart area, both anginal and other, episodes of dizziness, presyncope or syncope;
Signs of ventricular myocardial hypertrophy (mainly left);
Signs of impaired diastolic ventricular function;
Signs of obstruction of the output tract of the left ventricle (not in all patients);
Heart rhythm disturbances (most often atrial fibrillation). A certain staging of the course of HCM should be taken into account. Initially, when the pressure gradient in the outflow tract of the left ventricle does not exceed 25-30 mm Hg, there are usually no complaints. With an increase in pressure gradient up to 35-40 mm Hg. there are complaints about a decrease in tolerance to physical activity. When the pressure gradient reaches 45-50 mm Hg. a patient with HCM complains of shortness of breath, palpitations, angina, fainting. At a very high pressure gradient (>=80 mm Hg), hemodynamic, cerebrovascular and arrhythmic disorders increase.
In connection with the foregoing, the information obtained at various stages of the diagnostic search can be very different.
Yes, on first stage of diagnostic search there may be no complaints. With severe disorders of cardiac hemodynamics, patients present with the following complaints:
Shortness of breath during physical exertion, usually moderate, but sometimes severe (primarily due to diastolic dysfunction of the left ventricle, manifested in violation of its diastolic relaxation due to increased myocardial stiffness and, as a result, leading to a decrease in filling of the left ventricle during diastole, which, in turn, leads to an increase in pressure in the left atrium and end-diastolic pressure in the left ventricle, stagnation of blood in the lungs, the appearance of shortness of breath and a decrease in exercise tolerance);
On pain in the region of the heart, both a typical anginal character and atypical:
Typical anginal pain behind the sternum of a compressive nature that occurs during exercise and less often at rest is a manifestation of myocardial ischemia that occurs as a result of a disproportion between the increased oxygen demand of the hypertrophied myocardium and reduced blood flow in the myocardium of the left ventricle due to its poor diastolic relaxation;
In addition, hypertrophy of the media of small intramural coronary arteries can play a certain role in the development of myocardial ischemia, leading to narrowing of their lumen in the absence of atherosclerotic lesions;
Finally, in individuals over 40 years of age with risk factors for developing coronary artery disease, a combination of an increase in coronary atherosclerosis and HCM cannot be excluded;
Dizziness, headaches, tendency to faint
The consequence of a sudden decrease in cardiac output or paroxysms of arrhythmias, which also reduce output from the left ventricle and lead to a temporary impairment of cerebral circulation;
Heart rhythm disturbances, most often paroxysms of atrial fibrillation, ventricular extrasystole, PT.
These symptoms are observed in patients with severe HCM. With mild myocardial hypertrophy, a slight decrease in diastolic function and the absence of left ventricular outflow obstruction, there may be no complaints, and then HCM is diagnosed by chance. However, in some patients with sufficiently pronounced changes in the heart, the symptoms are indefinite: pains in the region of the heart are aching, stabbing, quite long.
With heart rhythm disturbances, complaints of interruptions, dizziness, fainting, transient shortness of breath appear. In the anamnesis, it is not possible to associate the appearance of symptoms of the disease with intoxication, past infection, alcohol abuse, or any other pathogenic influences.
Ha second stage of diagnostic search the most significant is the detection of systolic murmur, altered pulse and displaced apex beat.
Auscultation reveals the following features:
The maximum sounding of systolic murmur (ejection murmur) is determined at the Botkin point and at the apex of the heart;
Systolic murmur in most cases increases with a sharp rise of the patient, as well as during the Valsalva test;
II tone is always preserved;
Noise is not conducted on the vessels of the neck.
The pulse in about 1/3 of the patients is high, fast, which is explained by the absence of narrowing in the outflow tracts from the left ventricle at the very beginning of systole, but then, due to the contraction of powerful muscles, a “functional” narrowing of the outflow tracts appears, which leads to a premature decrease in pulse rate. waves.
The apex beat in 34% of cases has a "double" character: at first, on palpation, a blow is felt from the contraction of the left atrium, then from the contraction of the left ventricle. These properties of the apex beat are better detected in the position of the patient lying on his left side.
On the third stage of diagnostic search EchoCG data are of the greatest importance:
Hypertrophy of the myocardial wall of the left ventricle, exceeding 15 mm, in the absence of other visible causes that can cause it (hypertension, valvular heart disease);
Asymmetric hypertrophy of the interventricular septum, more pronounced in the upper third;
Systolic movement of the anterior leaflet of the mitral valve, directed forward;
Contact of the anterior leaflet of the mitral valve with the interventricular septum in diastole;
Small size of the cavity of the left ventricle.
Nonspecific signs include an increase in the size of the left atrium, hypertrophy of the posterior wall of the left ventricle, a decrease in the average speed of the diastolic cover of the anterior leaflet of the mitral valve.
ECG changes depend on the severity of left ventricular hypertrophy. With slight hypertrophy, the ECG does not reveal any specific changes. With sufficiently developed left ventricular hypertrophy, its signs may appear on the ECG. Isolated hypertrophy of the interventricular septum causes the appearance of a Q wave of increased amplitude in the left chest leads (V 5 -V 6), which complicates the differential diagnosis with focal changes due to myocardial infarction. However, the prong 0 narrow, which makes it possible to exclude the postponed MI. In the course of the evolution of cardiomyopathy and the development of hemodynamic overload of the left atrium, signs of left atrial hypertrophy syndrome may appear on the ECG: P more than 0.10 s, increase in the amplitude of the P wave, the appearance of a two-phase wave P in lead V 1 with increased amplitude and duration of the second phase.
For all forms of HCM, a common symptom is the frequent development of paroxysms of atrial fibrillation and ventricular arrhythmias (extrasystole and PT). With daily monitoring (Holter monitoring) of the ECG, these heart rhythm disturbances are well documented. Supraventricular arrhythmias are detected in 25-50% of patients, ventricular tachycardia is detected in 25% of patients.
X-ray examination in the advanced stage of the disease can determine the increase in the left ventricle and left atrium, the expansion of the ascending aorta. The increase in the left ventricle correlates with the height of pressure in the left ventricle.
On FCG, the amplitudes of I and II tones are preserved (and even increased), which distinguishes HCM from aortic stenosis caused by fusion of the valve leaflets (acquired defect), and systolic murmur of varying severity is also detected.
The curve of the carotid pulse, in contrast to the norm, is two-peak, with an additional wave on the rise. Such a typical picture is observed only with a pressure gradient "left ventricle-aorta" equal to 30 mm Hg. With a greater degree of stenosis due to a sharp narrowing of the outflow tracts, only one flat top is determined on the carotid sphygmogram.
Invasive research methods (probing of the left parts of the heart, contrast angiography) are currently not required, since echocardiography provides quite reliable information for making a diagnosis. It allows you to identify all the signs characteristic of HCM.
Cardiac scanning (with a thallium radioisotope) helps to detect thickening of the interventricular septum and free wall of the left ventricle.
Since coronary atherosclerosis is diagnosed in 15-25% of patients, coronary angiography should be performed in older individuals with attacks of typical anginal pain, since these symptoms, as already mentioned, in HCM are usually caused by the disease itself.
Diagnostics
The diagnosis is based on the identification of typical clinical manifestations and data from instrumental research methods (mainly ultrasound and ECG).
The following symptoms are most characteristic of HCM:
Systolic murmur with an epicenter along the left edge of the sternum in combination with preserved II tone; preservation of I and II tones on FCG in combination with mesosystolic noise;
Severe left ventricular hypertrophy according to ECG;
Typical signs found on echocardiography.
In diagnostically difficult cases, coronary angiography and MSCT of the heart with contrast are indicated. Diagnostic difficulties are due to the fact that individual symptoms of HCM can occur in a wide variety of diseases. Therefore, the final diagnosis of HCM is possible only with the obligatory exclusion of the following diseases: stenosis of the aortic orifice (valvular), mitral valve insufficiency, coronary artery disease, hypertension.
Treatment
The tasks of treating patients with HCM include:
Providing symptomatic improvement and prolongation of life to patients by influencing the main hemodynamic disorders;
Treatment of possible angina pectoris, thromboembolic and neurological complications;
Reducing the severity of myocardial hypertrophy;
Prevention and treatment of arrhythmias, heart failure, prevention of sudden death.
The question of the appropriateness of treating all patients remains debatable. Patients with an uncomplicated family history, without pronounced manifestations of left ventricular hypertrophy (according to ECG and echocardiography), life-threatening arrhythmias are indicated for dispensary observation with systematic ECG and echocardiography. They need to avoid significant physical activity.
Modern options for the treatment of patients with HCM include drug therapy (beta-blockers, Ca-channel blockers, antiarrhythmic drugs, drugs used to treat heart failure, prevent thromboembolic complications, etc.), surgical treatment in patients with severe obstruction of the outflow tract of the left ventricle (septal myectomy, alcohol ablation of the interventricular septum) and the use of implantable devices (ICD and dual chamber pacemakers).
Medical treatment
The first-line drugs in the treatment of patients with HCM are beta-blockers, which reduce the pressure gradient (appearing or increasing during exercise) and myocardial oxygen demand, prolong the time of diastolic filling and improve ventricular filling. These drugs can be recognized as pathogenetic, since they also have antianginal and anti-ischemic effects. Various beta-blockers, both short-acting and long-acting, can be used: propranolol at a dose of 40-200 mg / day, metoprolol (metoprolol tartrate) at a dose of 100-200 mg / day, bisoprolol at a dose of 5-10 mg / day.
In a number of patients in whom beta-blockers were not effective or their appointment was impossible (pronounced bronchial obstruction), short-acting calcium antagonists - verapamil at a dose of 120-360 mg / day can be prescribed. They improve the relaxation of the left ventricular myocardium, increase its filling during diastole, in addition, their use is due to a negative inotropic effect on the ventricular myocardium, which leads to an antianginal and anti-ischemic effect.
In the presence of ventricular arrhythmias and insufficient antiarrhythmic efficacy of beta-blockers, amiodarone (cordarone) is prescribed at a dose of 600-800 mg / day in the 1st week, then 200-400 mg / day (under the control of Holter monitoring).
With the development of heart failure, diuretics (hydrochlorothiazide, furosemide, torasemide) and aldosterone antagonists are prescribed: veroshpiron *, spironolactone (aldactone *) in the required doses.
In obstructive HCM, the use of cardiac glycosides, nitrates, sympathomimetics should be avoided.
It is indicated in approximately 5% of all patients with HCM, in the presence of severe left ventricular outflow obstruction, when the peak pressure gradient, according to Doppler ultrasound, exceeds 50 mm Hg. at rest and severe clinical symptoms persist (syncope, shortness of breath, angina pectoris, heart failure), despite the maximum possible drug therapy.
While doing septal myectomy resect a small area of the myocardium (5-10 g) of the proximal interventricular septum, starting from the base of the aortic annulus to the distal edge of the mitral valve cusps. At the same time, the output section of the left ventricle is expanded, its obstruction is eliminated, and at the same time, relative mitral valve insufficiency and mitral regurgitation are eliminated, which leads to a decrease in end-diastolic pressure in the left ventricle and a decrease in pulmonary congestion. Surgical mortality during this surgical intervention is low, it is 1-3%.
Percutaneous transluminal alcohol myocardial ablation ventricular septum was proposed in 1995 as an alternative to septal myectomy. Indications for its use are the same as for septal myectomy. This method is based on the creation of occlusion of one of the septal branches of the anterior interventricular coronary artery, which supplies blood to those parts of the interventricular septum that are responsible for the obstruction of the left ventricular outlet and pressure gradient. For this purpose, a small (1.0-3.0 ml) amount of ethanol is injected into the selected septal artery using the technique of percutaneous coronary interventions (PCI). This leads to the occurrence of artificial necrosis, i.e. MI of the area of the interventricular septum, responsible for the formation of obstruction of the output section of the left ventricle. As a result, the degree of ventricular septal hypertrophy decreases, the left ventricular outlets expand, and the pressure gradient decreases. Surgical mortality is approximately the same as with myectomy (1-4%), however, in 5-30% of patients, implantation of a pacemaker is required due to the development of atrioventricular block II-III degree.
Another method of surgical treatment of patients with HCM is implantation of a two-chamber (atrioventricular) pacemaker. During the implementation of electrical stimulation from the apex of the right ventricle, the normal sequence of contraction of various parts of the heart changes: initially, activation and contraction of the apex of the heart occur, and only then, with a certain delay, activation and contraction of the basal sections of the left ventricle. In some patients with left ventricular outflow obstruction, this may be accompanied by a decrease in the amplitude of motion of the basal sections of the interventricular septum and lead to a decrease in the pressure gradient. This requires a very careful individual adjustment of the pacemaker, which includes the search for the optimal value of the atrioventricular delay. Implantation of a dual chamber pacemaker is not the first choice in the treatment of patients with HCM. It is used quite rarely in selected patients over 65 years of age, with severe clinical symptoms, resistant to drug therapy, in whom myectomy or percutaneous transluminal alcohol ablation of the myocardium of the interventricular septum cannot be performed.
Prevention of sudden cardiac death
Among all patients with HCM, there is a relatively small group of patients characterized by a high risk of sudden cardiac death caused by ventricular tachyarrhythmias (ventricular fibrillation, ventricular tachycardia). This includes the following patients with HCM:
Previously transferred circulatory arrest;
Previous episodes of spontaneously occurring and sustained (lasting more than 30 seconds) ventricular tachycardia;
Having among close relatives of persons who suffered from HCM and died suddenly;
Suffering from unexplained episodes of loss of consciousness (syncope), especially if they are young people, and they experience syncope repeatedly and during physical exertion;
Having during 24-hour ECG Holter monitoring recorded episodes of unstable ventricular tachycardia (3 consecutive ventricular extrasystoles or more) with a frequency of more than 120 per minute;
Persons who develop arterial hypotension in response to physical activity performed in an upright position, especially young patients with HCM (under 50 years of age);
Having extremely pronounced hypertrophy of the left ventricular myocardium exceeding 30 mm, especially young patients.
By modern ideas in such patients with HCM who are at high risk of sudden cardiac death, implantation of an cardioverter-defibrillator is indicated for its primary prevention. It is even more indicated for the purpose of secondary prevention of sudden cardiac death in patients with HCM who have already experienced circulatory arrest or episodes of spontaneous and sustained ventricular tachycardia.
Forecast
Annual mortality is 3-8%, with sudden death occurring in 50% of such cases. Elderly patients die of progressive heart failure, and young patients die of sudden death due to the development of paroxysms of ventricular tachycardia or ventricular fibrillation, less often due to MI (which can also occur with little-changed coronary arteries). An increase in left ventricular outflow obstruction or a decrease in its filling during physical activity can also cause sudden death.
Prevention
Primary prevention measures are unknown.
Cardiomyopathies represent a heterogeneous group of myocardial diseases, the understanding of which has long been difficult. The term "cardiomyopathy" was proposed in 1957 to refer to myocardial damage of unknown cause. Further achievements molecular genetics in cardiology, clinical observations contributed to the promotion of a new understanding of cardiomyopathies, genetic defects that cause their development, diagnostic features, and pharmacotherapy.
In 2006 working group AHA (American Heart Association) formulated a definition of cardiomyopathies, reflecting the achievements of modern cardiology in understanding the essence of the disease: “Cardiomyopathies are a heterogeneous group of myocardial diseases, manifested by mechanical and / or electrical dysfunction, characterized by ventricular hypertrophy or dilatation, which develops due to various reasons, mainly genetic. Changes in cardiomyopathies may be limited to the heart or occur as systemic disorders, often leading to death or progressive heart failure.
Researchers consider two main groups of cardiomyopathies, common feature which is the defeat of the heart. TO primary cardiomyopathies include diseases limited to myocardial damage, in the development of which various factors participate: genetic, non-genetic (often mixed - genetic and non-genetic), acquired (Table 1). Secondary cardiomyopathies include myocardial damage associated with other systemic manifestations, while the symptoms of heart muscle disease do not necessarily predominate over other multi-organ signs.
genetic |
mixed |
Acquired |
Hypertrophic cardiomyopathy (HCM) |
Dilated cardiomyopathy (DCM) |
Inflammatory (myocarditis) |
Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) |
Restrictive (not hypertrophic or dilated) cardiomyopathy |
Stress-induced ("taco-tsubo") |
"Non-compact" left ventricular myocardium (LVNC) |
Periportal |
|
Glycogen storage - Danon, PRKAG2 |
Tachycardia-induced |
|
Conduction disorders (Lenegre disease) |
In children born to mothers with diabetes mellitus (insulin-dependent) |
|
Mitochondrial myopathies |
||
Ion channel diseases: prolongation of the QT interval (LQTS), Brugada syndrome, shortening of the QT interval (SQTS), catecholamine ventricular tachycardia (CPVT), idiopathic ventricular fibrillation (Asian SUNDS) |
Table 1. Classification of primary cardiomyopathies
Hypertrophic cardiomyopathy(HCM) refers to the primary genetically determined diseases and is the most common cardiomyopathy with a prevalence of 1:500 (according to the results of echocardiographic (EchoCG) examinations of the adult population). Currently, there is an increase in the number of registered cases of the disease, probably associated with the improvement of diagnostic equipment, research methods, as well as with an increase in the number of patients with HCM.
HCM is diagnosed in people of any age: from the first days of life to extreme old age, however, the disease is predominantly detected in people of young, working age. The prevalence of HCM does not depend on race or gender. Data on mortality in HCM varies significantly: in specialized centers that study cardiomyopathy, it is 3-6%; in the general population the figure is lower - 0.2%. Sudden cardiac death (SCD) and life-threatening cardiac arrhythmias are common causes of death in HCM in people of any age and in track and field athletes.
HCM is a disease with a characteristic complex of specific morphological and functional changes and myocardial hypertrophy (more than 15 mm) of the left and (or) right ventricle (in rare cases). Hypertrophy is often asymmetric due to thickening of the interventricular septum (IVS) with the development of obstruction of the outflow tract of the left ventricle (LV) in the absence of known causes (arterial hypertension, malformations and specific heart diseases). The disease is characterized by a progressive course with a high risk of developing severe life-threatening arrhythmias and SCD.
HCM is a clinically heterogeneous group of diseases inherited in half of the cases in an autosomal dominant manner. There are elderly patients with sporadic spontaneous mutations, i.e. having no relatives with HCM, with a high degree of penetrance - in 50% of cases they have a chance of passing the disease to their children. HCM is caused by more than 400 mutations in the genes encoding proteins of the myofibrillar apparatus. To date, 12 genes have been identified, each of which encodes components of the cardiac sarcomere protein and whose mutations can t lead to the development of HCM. These include genesβ-myosin, myosin-binding protein C, cardiac troponins T, C, I, myosin light chains, cardiac α-actin, titin, as well as protein kinase A, the gene for potassium voltage-gated channels. The most frequently observed damage to the genes encoding the synthesis of the heavy chain of β-myosin, myosin-binding protein C, troponin T, with a wide range of phenotypes that determine the age at which the disease manifests, clinical signs and patient life expectancy.
Certain mutations are known to be associated with a poor prognosis and a high incidence of SCD in HCM: Arg403Gln, Arg453Cys, Arg719Trp, Arg719Gln, Arg249Gln substitutions in the β-myosin heavy chain gene, InsG791 in the gene of myosin-binding protein C, and Asp175Asn in the α-tropomyosin gene. In the case of mutations in the troponin T gene, moderate myocardial hypertrophy is noted, but the prognosis of the disease remains unfavorable, since the risk of sudden cardiac arrest is high. Many genetic anomalies can present with a benign course and have a favorable prognosis.
Mutations appear that lead to LV hypertrophy, in addition to HCM, but they are characterized by extensive (more than 5%, without HCM - about 1%) histological changes in the form of classical signs (disarray phenomenon - disordered position of myofibrils and cardiomyocytes) and molecular disorders - excessive accumulation glycogen in cardiomyocytes (Table 2).
Primary genetic disorders associated with LV hypertrophy |
Diseases with metabolic disorders and LV hypertrophy |
Noon syndrome |
Newborns from mothers with diabetes mellitus |
Ataxia Frederick |
Amyloidosis |
Lentiginosis |
Glycogenoses |
Diseases with enhanced adaptive response in the form of LV hypertrophy |
Mitochondrial myopathies |
Renal and Afro-Caribbean hypertension |
Pheochromocytomas |
"Athletic" heart |
Congenital disorders of amino acid metabolism |
Obesity |
Fabry disease |
Table 2. Genetic syndromes and conditions associated with left ventricular hypertrophy
TO morphological manifestations , determined in HCM, also include areas of replacement of muscle tissue with fibrous tissue, thickening of the walls of the intramural coronary arteries, myocardial "bridges", an abnormal position of the coronary vessels, and minor anomalies of the heart. Significant violations of the sympathetic innervation of the heart are noted. Cardiomyocytes are usually overloaded with calcium, resulting in impaired ability to relax.
Classification HCM is based on the presence or absence of a pressure gradient in the LV cavity: obstructive And non-obstructive. There are three hemodynamic variants of obstructive HCM:
With subaortic obstruction at rest (basal);
With labile obstruction, characterized by significant spontaneous fluctuations in the intraventricular pressure gradient for no apparent reason;
With latent obstruction caused by physical and pharmacological (inhalation of amyl nitrite, intake of nitrates, intravenous isoproterenol) load.
There are five main variants of the course and outcomes of HCM:
Stable, benign course;
Sudden death;
progressive course;
- "final stage", due to the progression of heart failure;
Development of atrial fibrillation and related complications.
One of the mechanisms for the appearance of a pressure gradient in the LV cavity is obstruction, which occurs under the influence of the following factors: a decrease in the size of the outflow tract in diastole; LV hypertrophy, usually affecting the anterobasal regions; anterior displacement of the mitral valve towards the LV cavity with a decrease in its cavity; an increase in the size and size of the mitral valve cusps; hyperdynamic type of LV contractions, causing a high-speed flow through a narrowed outflow tract, as a result of which the mitral leaflets are attracted to the IVS, creating a Venturi effect; primary violations in the geometry of the left ventricle, affecting the papillary muscles and the mitral valve, increasing the tension of the tendon leaflet chords.
P. Spirito et al. proposed to distinguish three degrees of pressure gradient in the LV cavity:
Pressure gradient at rest or during challenge<30 мм рт.ст.;
Provoked obstruction - pressure gradient >50 mm Hg. when provoked, but<30 мм рт.ст. в покое;
Pressure gradient > 50 mmHg at rest.
Another mechanism for the appearance of a pressure gradient is considered in muscular obstruction in the middle part of the IVS. In this case, abnormal (hypertrophied, displaced) papillary muscles attached in short chords to the anterior leaflet of the mitral valve create an obstacle to blood flow from the LV outflow tract. Echocardiography from a parasternal short-axis position identifies papillary muscles, often located at 3 and 9 o'clock, in contrast to the position of papillary muscles in healthy individuals (at 4 and 8 o'clock). Obstruction also occurs when the hypertrophied IVS protrudes towards the free wall of the left ventricle, sometimes combined with apical hypokinesia in one or more segments.
In obstructive HCM with a pronounced subaortic gradient, primary mitral valve prolapse occurs in 3% of cases and mitral regurgitation is determined more often than in the non-obstructive form.
Clinical symptoms HCM can appear at any age, from early childhood to old age; they are nonspecific and varied. Symptoms are associated with hemodynamic disturbances: obstruction of the outflow tract of the left ventricle, relaxation disorders - diastolic dysfunction, mitral regurgitation; myocardial ischemia; violations of the autonomic regulation of the cardiovascular system, as well as electrophysiological processes in the heart.
The first clinical symptom of the disease in children, adolescents, young athletes during or after exercise is often sudden cardiac death.
Common symptoms in people with HCM are shortness of breath, weakness, and chest pain. Shortness of breath and weakness in many patients occur in the event of the development of diastolic dysfunction (systolic function remains unchanged) and precede the development of progressive heart failure. In the future, mixed (diastolic and systolic) dysfunction develops, accompanied by signs of circulatory failure, left ventricular or biventricular, often with dilatation of the heart chambers.
Chest pain resembles typical angina pectoris, as it occurs due to insufficiency of coronary blood flow with significant hypertrophy of the LV myocardium. At the same time, cardialgia is noted that develops with microcirculation disorders due to a decrease in blood flow in intramural vessels with increased wall thickness and partially narrowed during diastole. A certain role in the violation of blood flow in the epicardial coronary arteries is played by systolic obstruction by their muscular "bridges".
Syncope and lipothymia in patients with HCM are associated with paroxysmal arrhythmias (ventricular, supraventricular, tachy-, bradyarrhythmias); syndrome of small ejection, which is formed with severe obstruction of the output section of the left ventricle; neurocardiogenic autonomic dysfunction. The frequency of syncope varies: it occurs once or many times during a lifetime, however, regardless of the number of episodes, the sign is prognostically unfavorable and belongs to the main risk factors for SCD in patients with HCM (Table 3).
Table 3 Risk factors for sudden death in HCM
Cardiac arrhythmias are the most common cause of SCD in HCM. Asymptomatic course of arrhythmias is noted (25% of cases), as a rule, with intermittent ventricular tachycardia, as well as clinically manifesting arrhythmias, accompanied by typical subjective signs in the form of palpitations, "interruptions" in the work of the heart. The range of cardiac arrhythmias is diverse: extrasystole, supraventricular and ventricular tachycardia, bradyarrhythmia, atrial and ventricular fibrillation, blockade of the anterior and left bundle of His bundle. The causes of arrhythmias are considered to be the morphological disorganization of myofibrils, the presence of additional pathways, and the trigger is myocardial ischemia.
In a physical examination of patients with HCM, signs characteristic of LV hypertrophy are determined: amplification or double apex beat, displacement of the left border of the ratio severe dullness of the heart to the left and down; obstruction of its outlet: systolic trembling along the left edge of the sternum, blowing systolic murmur at the apex and along the left edge of the sternum, aggravated by exercise, Valsalva maneuver. The appearance of a systolic murmur of regurgitation in the region of the apex of the heart with irradiation to the left axillary region indicates LV dilatation and stretching of the atrioventricular ring.
The main diagnostic method HCM is an echocardiographic study that detects LV hypertrophy (usually asymmetric, with segmental or diffuse wall thickening), sometimes accompanied by a decrease in the size of the cavity. LV wall thickness (IVW) in HCM is 15 mm or more, but thinner thickness (13–14 mm) is also possible when other causes of LV hypertrophy are ruled out. In the case of asymmetric LV hypertrophy, an increase in the ratio of the thickness of the IVS to the thickness of the posterior wall in diastole of more than 1.6 is considered a sign of HCM. Anomalies of the papillary muscles (hypertrophy, topographic features), an increase in the size of the mitral valve leaflets, changes in LV geometry (hourglass shape due to narrowing of the outlet section), anterior systolic movement of the anterior leaflet of the mitral valve, systolic trembling of the aortic valve leaflets are described as non-permanent signs characteristic of obstructive HCM . In non-obstructive form, signs of hypertrophy of the apical region of the left ventricle are determined.
Of great importance for determining the prognosis of the disease is the measurement of the pressure gradient in the output section of the left ventricle by the Doppler method. An increased risk of SCD, progression of the disease, and the appearance of symptoms of severe heart failure are noted in the case of an increase in pressure gradient of more than 30 mm Hg. .
Electrocardiographic features in HCM are nonspecific, often including LV hypertrophy and end-ventricular complex changes. At the same time, blood flow disturbances in intramural vessels can be manifested by pathological Q waves in II, III, aVF and left chest leads, or as a result of IVS hypertrophy - in the right chest leads. Giant negative T waves in the precordial leads occur with LV apical hypertrophy.
Rhythm and conduction disturbances characteristic of HCM are diagnosed by dynamic recording of an electrocardiogram during the day (24-hour Holter monitoring). On a standard electrocardiogram in 12 leads, it is possible to detect extrasystole, premature ventricular excitation syndrome, blockade of the anterior and (or) left leg of the His bundle, and an extended QT interval.
Focusing on radiological signs of HCM is inappropriate, since they reflect symptoms typical of LV hypertrophy of any origin.
Treatment patients with HCM is determined according to the form of the disease, prognosis, risk of developing SCD, progression of heart failure, the presence or absence of life-threatening arrhythmias. The main goals of treatment are to alleviate the symptoms of the disease, prevent complications and prevent SCD.
General measures include limiting significant physical activity. The utility of treating non-obstructive HCM in asymptomatic patients is questionable.
If life-threatening arrhythmias (ventricular fibrillation, ventricular tachycardia) and major risk factors for SCD are identified, the most appropriate treatment option is implantation of a cardioverter-defibrillator (class I, level of evidence B; class IIa, level of evidence C) .
Drug treatment is carried out in the case of clinical manifestations of the disease in order to reduce the pressure gradient in the output section of the left ventricle, the degree of LV hypertrophy and correct signs of heart failure.
The main groups of drugs in the treatment of HCM are β-adrenergic blockers (BAB) and calcium channel blockers (CCBs), in case of cardiac arrhythmias - disopyramide and amiodarone.
Amiodarone is indicated for ventricular tachycardia and/or atrial fibrillation (class IIa, level of evidence C) in individuals without risk factors for SCD. For primary prevention of SCD, amiodarone is given to patients with HCM with one or no major risk factor for SCD (Class IIb, Level of Evidence C). With long-term administration of amiodarone, it is necessary to take into account its proarrhythmic effect (development of polymorphic ventricular tachycardia) and toxicity in 30% of cases (impaired function thyroid gland, development of pulmonary fibrosis, etc.).
BABs are among the drugs that can achieve an effect in the treatment of 30-60% of patients with obstructive and non-obstructive forms of HCM. Propranolol, atenolol, metoprolol, sotalol, nadolol reduce myocardial oxygen demand, reduce the activity of the sympathetic-adrenal system during physical and emotional stress, thereby improving the quality of life of patients: palpitations and shortness of breath decrease, the development of pain angina pectoris is stopped and (or) is prevented. β-blockers prevent an increase in the pressure gradient during latent and labile obstruction in the output section of the left ventricle, cause regression of myocardial hypertrophy. However, drugs of this class do not have a significant effect on the survival of patients with HCM.
Predominantly drugs without internal sympathomimetic activity are used. Accumulated experience in the use of average and maximum effective (120-240 mg) doses of propranolol. Start with 20 mg 3-4 times a day, gradually increase the dose until it is effective under the control of heart rate and blood pressure, but the use of large doses causes unwanted side reactions. In this case, resort to cardioselective BAB. In the event of the development of symptoms of chronic heart failure, such BABs as metoprolol, bisoprolol, carvedilol are prescribed in doses according to recommendations for the treatment of heart failure.
Treatment with calcium channel blockers is considered justified, pathogenetic compared to BAB, since drugs of this class reduce the level of free calcium in cardiomyocytes, normalizing their contraction, suppress the processes of myocardial hypertrophy, and reduce its contractility. Causing negative inotropic and chronotropic effects, CCBs reduce the subjective clinical signs of the disease.
Verapamil, which has a predominantly cardioprotective effect, as well as BAB, reduces myocardial oxygen consumption, reduces the manifestations of ischemia, improves LV diastolic function, increases exercise tolerance in patients, and reduces the subaortic gradient at rest. It provides effective treatment for 60-80% of patients with non-obstructive HCM, including those refractory to beta-blockers.
Since the use of verapamil is accompanied by a decrease in total peripheral vascular resistance and a decrease in afterload, in patients with significant obstruction, the LV pressure gradient may rapidly increase, resulting in pulmonary edema, cardiogenic shock, or SCD. Due to the risk of serious complications, verapamil is prescribed with caution in patients with high pressure in the pulmonary artery, severe LV outflow obstruction, and signs of cardiac asthma.
Apply verapamil (preferably sustained release forms) at a dose of 20-40 mg 3 times a day with a gradual increase (with good tolerance) to 160-240 mg under the control of heart rate (at rest 60 bpm). There is an opinion that the survival rate of patients with non-obstructive HCM treated with verapamil is higher than that of those receiving placebo. However, convincing data on the effectiveness of the effect of verapamil on the end points of treatment of patients with HCM (increased life expectancy) have not been obtained.
There is no evidence of the effectiveness of combined treatment of HCM, including beta-blockers and CCBs, compared with monotherapy. Most studies evaluating the results of treatment of patients with HCM are non-randomized and uncontrolled.
Disopyramide belongs to class IA antiarrhythmic drugs. It has a pronounced inotropic effect. In HCM, disopyramide (dose 300–600 mg/day) reduces the degree of anterior systolic movement of the mitral valve leaflet, obstruction and mitral regurgitation, and has a positive effect on the structure of diastole. However, the drug causes an acceleration of atrioventricular impulse conduction and an increase in heart rate, which has an adverse effect on hemodynamics.
The following criteria for effective treatment of patients with HCM have been defined:
Increase in life expectancy;
Reducing the degree of obstruction of the outflow tract of the left ventricle;
Absence of life-threatening arrhythmias, syncope, angina pectoris;
Prevention of the development of heart failure;
Improving the quality of life - a satisfactory tolerance of household physical activity.
There are significant difficulties in the treatment of patients with HCM with signs of chronic heart failure. Since the use of diuretics, angiotensin-converting enzyme (ACE) inhibitors, nitrovasodilators, cardiac glycosides leads to an increase in the pressure gradient in the left ventricle outlet and aggravation of the symptoms of the disease, their administration is contraindicated if an obstruction gradient is detected at rest and (or) during provocations.
At the same time, it is known that ACE inhibitors stimulate the regression of myocardial hypertrophy through direct blockade of the local renin-angiotensin-aldosterone system and prevent the action of angiotensin II and catecholamines on the myocardium. In the later stages of the disease, with severe systolic dysfunction and dilatation of the heart cavities (5% of patients), drug therapy is carried out in accordance with the recommendations for the treatment of congestive heart failure with the careful use of ACE inhibitors, cardiac glycosides, diuretics, angiotensin II receptor blockers, spironolactone. Evidence of the effectiveness of BAB in the final "dilatational" stage of HCM has not been received.
Surgical treatment of obstructive HCM has been performed since the 1960s. Potential candidates for surgical treatment are 5% of patients with obstructive HCM and refractoriness to drug therapy. Due to the improvement of surgical treatment methods (myoectomy, myoseptectomy), a decrease in surgical mortality is observed: 1–2% versus 2–5% against the background of drug therapy, however, surgical treatment does not have a significant effect on increasing the life expectancy of patients with HCM.
Along with surgical treatment, new methods are being developed - transcatheter alcohol septal ablation, dual-chamber pacing, which have certain advantages, but their effectiveness is still being studied. Thus, along with drug therapy, which does not allow to achieve positive results in all cases of the disease, surgical, minimally invasive, electrical methods of treating HCM are used.
Patients with obstructive HCM are at risk of developing infective endocarditis. In order to prevent the disease, antimicrobial therapy is recommended before performing dental, endoscopic, "small" surgical procedures.
Thus, hypertrophic cardiomyopathy is one of the diseases, the diagnosis of which is possible at later stages, in case of development of serious complications. The complex mechanisms of the symptoms of the disease, difficulties in choosing therapy, insufficient knowledge of its long-term results and the lack of an evidence base determine the further study of HCM.
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Cardiomyopathies are diseases in which myocardial damage is a primary process, and not a consequence of hypertension, congenital diseases, damage to valves, coronary arteries, and pericardium. Cardiomyopathies are not considered as the leading pathology of the heart in Western countries, while in a number of underdeveloped countries they cause 30% or more of all deaths due to heart disease. According to the classification based on etiological signs, there are two main types of cardiomyopathy: the primary type, which is a disease of the heart muscle of an unknown cause; secondary type, in which the cause of myocardial disease is known or associated with damage to other organs (Table 192-1). In many cases, the establishment of an etiological diagnosis in the clinic is not possible, so it is often considered preferable to classify cardiomyopathies based on differences in their pathophysiology and clinical manifestations (Tables 192-2 and 192-3). The differences between functional categories, however, are not absolute and often overlap.
Dilated (congestive) cardiomyopathy
An increase in the size of the heart and the appearance of symptoms of congestive heart failure leads to a violation of the systolic function of the heart. Parietal thrombi are often observed, especially in the region of the apex of the left ventricle. Histological studies revealed intense fields of interstitial and perivascular fibrosis with minimal severity of necrosis and cell infiltration. Although the etiology of the disease is often unclear, dilated cardiomyopathy (formerly called congestive cardiomyopathy) appears to be the end result of myocardial damage from various toxic, metabolic, or infectious agents. There is good reason to believe that, in at least some patients, dilated cardiomyopathy may be a late stage of acute viral hepatitis, probably enhanced by the action of immune mechanisms. Persons of both sexes and any age get sick, although middle-aged men are more common. If dilated cardiomyopathy is associated with selenium deficiency, it may be reversible.
Cardiomyopathy. Clinical manifestations. Most patients gradually develop left and right ventricular congestive heart failure, manifested by dyspnea on exertion, fatigue, orthopnea, paroxysmal nocturnal dyspnea, peripheral edema, and palpitations. In some patients, left ventricular dilatation exists for months or even years before it manifests itself clinically. Although chest pain is a concern for patients, typical angina is rare and suggests concomitant coronary artery disease.
Cardiomyopathy. Physical examination. When examining a patient, various degrees of enlargement of the heart and congestive heart failure are revealed. In patients with severe forms of the disease, a small pulse pressure and increased pressure in the jugular veins are detected. Often there are III and IV heart sounds. Mitral and tricuspid regurgitation may develop. Diastolic murmurs, valvular calcification, hypertension, and vascular changes in the fundus argue against the diagnosis of cardiomyopathy.
Table 192-1. Etiological classification of cardiomyopathies
I. With primary myocardial involvement
A. Idiopathic (D, R, H)
B. Family (D, H)
B. Eosinophilic endomyocardial disease (R)
Cardiomyopathy
Description of cardiomyopathy
Distinguish primary cardiomyopathies And secondary cardiomyopathies. or symptomatic. Primary, or idiopathic, myocardiopathies include myocardial lesions of unknown etiology, they are relatively rare. Secondary, or symptomatic, cardiopathy in the domestic literature are combined under the name of myocardial dystrophy and are described in a special section.
Primary cardiomyopathies include non-obstructive idiopathic myocardial hypertrophy. This disease is characterized by enlargement of the heart and symptoms of congestive heart failure. First, the walls of the myocardium thicken due to hypertrophy. Only in the later stages do dilatation of the cavities of the heart and a significant increase in its size join. Histological examination does not reveal inflammatory changes. The disease occurs at the age of 20-50 years, mainly in men. The main but late clinical manifestation is progressive heart failure, initially left ventricular, but quickly becoming total. Heart failure is difficult to treat. Sometimes there are disturbances of excitability or conduction (paroxysmal tachycardia, different kinds blockade).
An objective examination revealed a moderate increase in the size of the heart, especially the left ventricle. On auscultation, a systolic murmur is heard at the apex, not coarse, blowing. The gallop rhythm is often determined.
Radiological and electrocardiographic signs of left ventricular hypertrophy are revealed, sometimes long before the onset of symptoms of heart failure.
Diagnosis of cardiomyopathy
Echocardiography is of great diagnostic value.
Diagnosis of the disease is difficult, as with all primary cardiopathies, and the diagnosis is made mainly by exclusion. We often have to resort to catheterization of the heart cavities, angiocardiography, myocardial biopsy. The differential diagnosis with IHD is especially difficult.
Idiopathic obstructive myocardial hypertrophy can occur in children, but more often it affects people of mature age. The disease can be familial or endemic, occurring in certain areas. In this disease, the myocardium is hypertrophied mainly in the outflow tract from the left ventricle with difficulty in ejection of blood into the aorta. Because of this, some authors call the disease "muscular subaortic stenosis." Histologically, the myocardium shows pronounced signs of its hypertrophy without inflammatory or sclerotic changes. The interventricular septum is especially hypertrophied.
Complaints in this disease are absent for a long time, and the symptoms of the disease occur late. This is shortness of breath on exertion, palpitations. Stagnation is rare and occurs in the later stages. Attacks of stenocardia are often observed. Arrhythmias are rare. An objective examination reveals an increase in the left ventricle, very moderate. A systolic rather coarse murmur, III tone, is auscultated. The most intense systolic murmur to the left of the sternum. X-ray examination reveals an increase in the left ventricle with an unchanged or hypoplastic aorta. The ECG shows a typical pattern of left ventricular hypertrophy. Echocardiography is especially informative in determining left ventricular hypertrophy.
The disease flows latently, and sometimes patients die suddenly. Having appeared, heart failure progresses rapidly.
Familial cardiomegaly
The disease wears family character, affects certain ethnic groups and appears to be genetically determined. Histologically, hypertrophy of muscle fibers and fibrosis are found in the myocardium. This disease is rare. Initial symptoms are shortness of breath, palpitations. Often there are various arrhythmias and conduction disorders.
An objective examination reveals a significant increase in the size of the heart without severe symptoms of heart failure. X-ray examination revealed cardiomegaly. On the ECG, in addition to rhythm and conduction disturbances, various changes in the 5T segment and the T wave are found.
For the diagnosis of the disease, a family history, examination of the next of kin of the patient is essential.
Endomyocardial fibrosis and endocardial fibroelastosis are rare in adult cardiopathy, more often they occur in childhood.
Both diseases are characterized by endocardial fibrosis with its thickening, difficulty in emptying the heart cavities, the development of myocardial hypertrophy, and then heart failure without dilatation of the heart. In endomyocardial fibrosis, in addition to the endocardium, the inner layers of the myocardium are also affected. These diseases are more common in Africa, where they are endemic.
The disease begins in childhood or adolescence with complaints of weakness, fatigue. In the future, heart failure develops, more often right ventricular. An objective study reveals an increase in the size of the heart, a systolic murmur, very similar to a murmur in mitral insufficiency. On the ECG and X-ray examination, signs of left ventricular hypertrophy are found.
The differential diagnosis is very difficult and is sometimes established only after endomyocardial biopsy.
Treatment of cardiomyopathy
Treatment of cardiomyopathies essentially symptomatic and aimed at combating heart failure and arrhythmias. In cases of obstructive type hypertrophy in the absence of symptoms of heart failure, the use of blockers (3-adrenergic receptors in moderate doses (20-40 mg per day) is indicated. The prognosis of primary cardiomyopathies is always serious.
This section includes several dozen articles on heart diseases, among these diseases are such as
Diagnosis of hypertrophic cardiomyopathy
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Consultations with a German specialist for treatment in Germany
General medical examination
Most often, hypertrophic cardiomyopathy is not detected by auscultatory methods. Usually heart sounds are not changed, although with a significant pressure gradient between the aorta and the left ventricle, paradoxical splitting of the II tone may occur. With obstruction of the outflow tract of the left ventricle, the main auscultatory manifestation of the pathology under consideration is systolic murmur, the occurrence of which is associated with mitral regurgitation and the presence of an intraventricular pressure gradient between the aorta and the left ventricle.
The murmur has a decreasing-increasing character and is best heard between the left edge of the sternum and the apex of the heart. May radiate to the armpit. The noise decreases with a decrease in myocardial contractility, an increase in blood pressure, or an increase in the volume of the left ventricle. It increases with an increase in myocardial contractility (for example, during exercise), a decrease in blood pressure, or a decrease in the volume of the left ventricle.
Also, during the examination, the doctor is recommended to pay attention to signs of the presence of systemic diseases associated with hypertrophic cardiomyopathy: Noonan syndrome, facial dimorphia, Fabry disease, as well as typical maculopapular skin lesions.
ECG
In 75-95% of cases of hypertrophic cardiomyopathy, the patient's electrocardiogram shows changes corresponding to left ventricular hypertrophy: changes in the T wave and the ST segment, atrial flutter and fibrillation, the presence of pathological Q waves (in the chest leads, in leads aVF, II, III), shortening interval P-Q(P-R), ventricular extrasystole, and incomplete bundle branch block.
The reasons for the appearance of pathological Q waves on the ECG have not been established, they are associated with abnormal activation of the interventricular septum, myocardial ischemia, and an imbalance in the resulting electrical vectors of the right ventricular wall and interventricular septum.
Also, in more rare cases, atrial fibrillation and ventricular tachycardia are observed in patients with hypertrophic cardiomyopathy. In the presence of apical cardiomyopathy, negative T waves with a depth of more than 10 mm are often observed in the chest leads.
echocardiography
Echocardiography is the main method for diagnosing this pathology. With the help of this study, the severity of hypertrophy, the localization of hypertrophied areas of the myocardium, and the presence of obstruction of the outflow tract of the left ventricle are determined.
In the Doppler mode, the degree of pressure gradient between the aorta and the left ventricle is determined (if we are talking about a gradient over 50 mm Hg, it is considered pronounced) and the severity of mitral regurgitation. In addition, in this mode it is possible to identify concomitant moderate or minor aortic regurgitation, which occurs in 30% of patients with hypertrophic cardiomyopathy.
In 80% of patients with this pathology, signs of diastolic dysfunction of the left ventricle can be detected. The ejection fraction can also be increased. In addition, the signs of hypertrophic cardiomyopathy include:
- Dilatation of the left atrium;
- Small volume of the cavity of the left ventricle;
- Mid-systolic closure of the aortic valve cusps;
- Reduced range of motion of the interventricular septum with increased or normal motion of the posterior wall of the ventricle.
Signs of obstructive hypertrophic cardiomyopathy detected by echocardiography include:
- Asymmetric hypertrophy of the interventricular septum with a ratio of its thickness to the thickness of the posterior wall of the ventricle of more than 1.3:1. In this case, the thickness of the interventricular septum should be 4-6 mm higher than that established for this age group norm;
- Systolic anterior displacement of the anterior leaflet of the mitral valve.
Other display methods
The maximum wall thickness and determination of the mass of the muscular wall of the left ventricle can also be determined by cardio-MRI and CT. A recently published study suggests a relationship between fibrosis size and risk of ventricular arrhythmias. The relationship between impaired microcirculation and the resulting scarring with a tendency to arrhythmias has already been described previously.
Load tests
In patients with hypertrophic cardiomyopathy, it is recommended to check the ability to carry out physical activity, since the subjective assessment of this parameter often gives incorrect data. Also during this test, doctors receive information about the values blood pressure patient at rest and during exercise.
Rhythm test
A 48-hour Holter ECG can detect short-term ventricular tachycardias, which are essential for making a diagnosis. For recent years invasive ECG has lost its importance, it is increasingly carried out only with a targeted examination (for example, with suspicion of SVC syndrome).
Invasive diagnostics
Invasive diagnostic techniques are used to confirm or prove coronary sclerosis by imaging the vascular supply of the septum prior to scheduled septumablation. Myocardial biopsy may be done to rule out amyloidosis. Invasive determination of the significance of sclerosis is rarely required.
Molecular genetics
In the presence of hypertrophic cardiomyopathy in a family history, it is necessary to examine the genome of children for the presence of this pathology. If the examination of the genes in early age has not been performed, then echocardiography should be performed between the 12th and 18th years of life once a year, and once every five years after 18 years.
Differential Diagnosis
When making a diagnosis of "hypertrophic cardiomyopathy" in the first place, you need to exclude other possible reasons occurrence of left ventricular hypertrophy. First of all, the pathologies that cause this deviation include a sports heart and essential arterial hypertension (with a tendency to high blood pressure). If there is a suspicion of obstructive hypertrophic cardiomyopathy, special attention should be paid to the differential diagnosis with heart defects that are accompanied by systolic murmur (primarily diseases with aortic stenosis, mitral valve insufficiency or ventricular septal defect).
In patients with focal and ischemic changes on the ECG and / or anginal pain, it is first necessary to rule out CAD. If the clinical picture is dominated by symptoms characteristic of congestive heart failure, hypertrophic cardiomyopathy should be distinguished from idiopathic dilated cardiomyopathy, as well as from diseases of the myocardium and pericardium that occur with a restriction syndrome: cardiomyopathy with amyloidosis / sarcoidosis / hemochromatosis, constrictive pericarditis, and also from idiopathic restrictive cardiomyopathy.
sports heart
Differential diagnosis of non-obstructive hypertrophic cardiomyopathy (especially if left ventricular hypertrophy is relatively mild - wall thickness is in the range of 14-15 mm) and sports heart is a rather difficult task. It acquires particular importance in the light of the fact that hypertrophic cardiomyopathy is the main cause of sudden cardiac death among young professional athletes, which means that this diagnosis leads to their immediate disqualification.
In some controversial cases, a high probability of hypertrophic cardiomyopathy is indicated by the identification during Doppler echocardiography of an unusual distribution of myocardial hypertrophy, an increase in the size of the left atrium, a decrease in the end-diastolic diameter of the left ventricle to a level of less than 45 mm, and other signs of the presence of violations of the diastolic filling of the left ventricle.
ischemic heart disease
Most often, there is a need to differentiate hypertrophic cardiomyopathy from chronic and, in more rare cases, acute forms of coronary heart disease. Echocardiography is very important for making a correct diagnosis - in a number of patients with coronary heart disease, this study determines moderate dilatation of the left ventricle, a decrease in its EF, and the presence of segmental contractility disorders. Elderly patients may have aortic valve calcification.
Hypertrophic changes in the left ventricle are very moderate, most often they are symmetrical. A visible disproportionate increase in the thickness of the interventricular septum may be a consequence of postinfarction cardiosclerosis in the area of the posterior wall of the left ventricle, which was accompanied by compensatory hypertrophy of the septum. At the same time, in contrast to the picture in hypertrophic cardiomyopathy, hyperkinesia is observed.
Hypertrophic cardiomyopathy can be confirmed by detecting signs of subaortic obstruction during Doppler echocardiography. In its absence, the differential diagnosis is significantly complicated.
Since exercise tests can give positive results in both cases, the only reliable method for confirming or excluding CAD in patients with hypertrophic cardiomyopathy is radiopaque coronary angiography. It is important to note that in patients of the middle and older age groups - especially males - these diseases may well be combined and present together.
Essential arterial hypertension
The most difficult thing to diagnose is hypertrophic cardiomyopathy, which occurs with a moderate increase in blood pressure - this form of pathology is very similar to isolated arterial hypertension, accompanied by disproportionate thickening of the interventricular septum and left ventricular hypertrophy.
The likely presence of essential arterial hypertension is indicated by a persistent and significant increase in blood pressure, the presence of retinopathy and crises, as well as an increase in the thickness of the middle and inner membranes of the carotid arteries, which is not characteristic of hypertrophic cardiomyopathy.
In favor of hypertrophic cardiomyopathy, the presence of a subaortic gradient or, in its absence, a significant severity of asymmetric hypertrophic changes in the interventricular septum (an increase in its thickness by 2 or more times compared to the posterior wall of the left ventricle) speaks in favor of hypertrophic cardiomyopathy. You can also talk about the presence of the disease in question if it is present in a family history. Recently, various authors have paid great attention to the definition of criteria for the differential diagnosis of cardiomyopathy among the Doppler echocardiography indicators, which characterize violations of the diastolic function of the left ventricle.
Primary mitral valve insufficiency
For mitral insufficiency. having a rheumatic origin, a characteristic feature is the systolic nature of the noise. When conducting EchoCG, an increase in the cavity of the left ventricle and, in some cases, signs of valve fibrosis are observed. Important for differential diagnosis is the nature of the change in the magnitude of the reverse blood flow, obtained from the data of phonocardiography, auscultation and Doppler echocardiography under the influence of the dynamics of pre- and afterload of the left ventricle during a change in body position, the introduction of vasodilator and vasopressor drugs, as well as the Valsalva test.
In mitral insufficiency with rheumatic etiology, the volume of regurgitation increases with an increase in blood pressure and decreases with a decrease in venous inflow after inhalation of amyl nitrite or in a standing position. In hypertrophic cardiomyopathy, the picture is opposite.
Some difficulties may occur in the differential diagnosis of hypertrophic cardiomyopathy with primary mitral valve prolapse accompanied by regurgitation. With both pathologies, a tendency to dizziness, palpitations and fainting is noted; late systolic murmurs over the upper part of the heart and the same nature of their dynamics under the influence of pharmacological and physiological tests.
At the same time, with primary mitral valve prolapse, there is an absence of ischemic and focal changes on the ECG, as well as a lower severity of left ventricular hypertrophy than with hypertrophic cardiomyopathy. The basis for the final diagnosis may be the data of doppler echocardiography - including transesophageal.
Aortic stenosis
In some cases, the epicenter of the systolic murmur of valvular stenosis of the aortic orifice is fixed above the apex of the heart and at the Botkin point, which is similar to the auscultatory picture of obstructive hypertrophic cardiomyopathy. Both pathologies are characterized by shortness of breath, the occurrence of anginal pain, fainting, dizziness, changes in the T wave and the ST segment on the ECG, signs of left ventricular hypertrophy and an increase in the thickness of its myocardium with a constant or reduced volume of its cavity, which is shown by echocardiography.
The likely presence of stenosis of the aortic orifice is evidenced by changes in the second tone, the presence of post-stenotic expansion of the ascending aorta, systolic murmur during auscultation on the vessels of the neck, the presence of signs of calcification and fibrosis on radiography and echocardiography, as well as the similarity of the sphygmogram with a cockscomb. Also, the identification of the systolic pressure gradient in the aortic valve area during cardiac catheterization and Doppler echocardiography can help confirm the diagnosis.
Ventricular septal defect
In the asymptomatic course of the disease in young patients with coarse systolic murmurs in the area of the 3rd-4th intercostal space at the left edge of the sternum, as well as with signs of hypertrophic changes in the left ventricle, it becomes necessary to conduct a differential diagnosis of ventricular septal defect and hypertrophic cardiomyopathy.
The hallmarks of this birth defect when conducting a non-invasive examination are:
- Noticeable enlargement of the pulmonary artery arch on cardiac radiographs;
- Heart hump;
- Systolic trembling in the area of listening to noise.
The final diagnosis can be made using Doppler echocardiography, in the most difficult cases, an invasive examination of the heart is performed.
General information
In general, the following facts allow suggesting the diagnosis of "hypertrophic cardiomyopathy":
- Patient complaints of shortness of breath, fainting and anginal pain, especially in young people. A little less than half of all patients are noted;
- Cases of sudden cardiac death in the family, especially in combination with ECG signs of clinically unexplained left ventricular hypertrophy, ischemic ST segment depression, and deep negative G waves.
Diagnosis is based on the identification of varying degrees of myocardial hypertrophy using echocardiography, radiopaque angiocardiography, or the most informative method - MRI. Hypertrophy is exposed to one or more segments of the left ventricle, sometimes the right ventricle. This process, most often, although not necessarily, is asymmetric with a predominant localization in the basal part of the interventricular septum and cannot be explained by other heart diseases or systemic pathologies. In this case, most often there is a characteristic combination of left ventricular hypertrophy itself and a decrease in the volume of its cavity with an increase in EF.
The diagnosis of "hypertrophic cardiomyopathy with obstruction" can be made when a specific late systolic murmur is detected in a patient with the pathology under consideration, which is heard above the apex of the heart, as well as at the Botkin point. The murmur is exacerbated by standing, inhaling amyl nitrite, and performing the Valsava maneuver, and echocardiography reveals anterior systolic movement of the mitral valve leaflets (anterior and/or posterior) in combination with their contact with the interventricular septum.
Additional signs of pathology include the presence of moderate late mitral regurgitation and midsystolic aortic valve closure. Diagnosis can be clarified by the detection of more than 30 mm Hg. Art. systolic pressure gradient between the outflow tract of the left ventricle and the body - for this, Doppler echocardiography is performed. Also, data can be obtained directly - during cardiac catheterization. With obstruction at rest, this gradient is recorded in basal conditions, it increases during provocative tests. At the same time, with latent obstruction, the gradient occurs only during the execution of provocative tests.
The presence of a subaortic gradient is unequivocal evidence in favor of hypertrophic cardiomyopathy. Less accurate - even when using modern technologies magnetic resonance imaging - is the identification of non-obstructive hypertrophic cardiomyopathy (especially if hypertrophy is limited or mild). In this case, confirmation of the diagnosis is possible only if specific mutations are detected during a genetic study.
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Cardiomyopathy is a group of inflammatory diseases of the myocardium with different etiologies. At the same time, the heart muscle is changed both structurally and functionally (thickening of the partitions or walls of the myocardium, enlargement of the heart chambers, etc.). Previously, these diseases were called myocardial dystrophy. The disease cardiomyopathy is equally common between men and women and can affect a person at any age.
Varieties of cardiomyopathy
There are three types of cardiomyopathy:
- hypertrophic;
- dilatational;
- restrictive.
Each variety of the disease affects the myocardium in its own way, however, the principles of their treatment are similar, mainly they are aimed at treating chronic heart failure and eliminating the causes that caused cardiomyopathy.
Hypertrophic
Hypertrophic cardiomyopathy (HCM) is a significant thickening (hypertrophy) of the interventricular septum or wall of the left ventricle, while the volumes of the ventricular cavities remain normal. In this cardiomyopathy, the cause of sudden death can be significant and sudden disturbances in the heart rhythm. In many athletes who died during training, it was the hypertrophic form of cardiomyopathy that was identified. Against the background of a violation of the ability to relax the left ventricle, heart failure may gradually develop, which may not manifest itself clinically for a long time. This cardiac chamber, up to the terminal stage, retains normal contractility, but as the disease progresses, a local thickening forms in the myocardium, which leads to a change in the shape of the left ventricle. In the future, the pathogenesis of cardiomyopathy is as follows: the walls of the outflow tract become smaller, and the septa thicken. The distensibility of all cardiac chambers also becomes less.
Dilated
With dilated cardiomyopathy (DCM), dilatation occurs in the heart cavities (an increase in the volume of all cardiac chambers) without thickening of the myocardial walls, which leads to systolic dysfunction. Manifested by a violation of the contractile function of the heart muscle
Restrictive
The least common is restrictive cardiomyopathy of the heart, in which the walls of the organ become rigid (increased myocardial rigidity), with difficulty passing into the relaxation stage, that is, it reduces the ability to relax the heart walls. As a result of this, the delivery of oxygen-rich blood to the left ventricle is difficult, and the blood circulation in the whole body is also disturbed. The load increases, leading to thickening of the walls of the atria, while the state of the ventricles remains the same.
This type of cardiomyopathy is sometimes observed in children against the background of the presence of hereditary factors.
Causes of cardiomyopathy
In cardiomyopathy, myocardial damage can be a primary or secondary process caused by systemic diseases that lead to the development of heart failure, and occasionally even to sudden death.
The causes of primary cardiomyopathy can be divided into three groups:
- congenital;
- acquired;
- mixed.
Secondary cardiomyopathies are called, resulting from a particular disease.
Congenital pathology of the heart occurs due to a violation of the formation during embryogenesis of myocardial tissues. There can be many reasons for this: starting from the mother's bad habits and finishing it proper nutrition and stress. In addition, there are cardiomyopathies in pregnant women and inflammatory cardiomyopathies, which are essentially myocarditis.
Secondary forms of cardiomyopathy include:
- infiltrative or storage cardiomyopathy, in which pathological inclusions are concentrated in cells or in the intercellular space.
- Toxic cardiomyopathy. When the heart muscle interacts with drugs (primarily with antitumor drugs), the severity of its damage can be different: sometimes these are only asymptomatic changes on the electrocardiogram, but there is also instant heart failure with a fatal outcome. The etiology of cardiomyopathy knows a lot of such examples, when, as a result of long-term use of large doses of alcohol, inflammation of the myocardium occurs in people (alcoholic cardiomyopathy). In Russia, this particular reason is in the first place of all those identified for this disease.
- Endocrine cardiomyopathy, subdivided into metabolic and dysmetabolic forms, occurs against the background of metabolic disorders in the myocardium. The disease often causes dystrophy of the walls of the myocardium and a violation of its contractility. Illness can be caused by illness endocrine system, obesity, menopause, diseases of the intestines and stomach, unbalanced nutrition. If the causes of cardiomyopathy are diabetes mellitus or thyroid dysfunction, then they speak of hypertrophic cardiomyopathy.
- TO nutritional cardiomyopathy I can cite eating disorders, for example, unreasonably long diets with restriction of animal protein, starvation. The work of the heart is negatively affected by the lack of consumption of carnitine, selenium, vitamin B1.
Symptoms of cardiomyopathy
Depending on the form of the disease, the symptoms of cardiomyopathy also differ, so it is difficult to distinguish common characteristic signs. We will consider the symptoms of each individual type of cardiomyoptia.
The most characteristic symptoms of dilated cardiomyopathy are:
- frequent increase in blood pressure;
- fast fatiguability;
- pallor of the skin;
- the appearance of edema on the lower extremities;
- cyanosis of the fingertips;
- even with slight exertion, shortness of breath occurs.
This symptomatology is caused by progressive heart failure.
Signs of hypertrophic cardiomyopathy:
- pain in the chest area;
- dyspnea;
- heartbeat;
- tendency to faint;
In restrictive cardiomyopathy, there is an increase in myocardial stiffness, which reduces the ability to relax the heart walls. With restrictive cardiomyopathy, the medical history often contains episodes when patients begin to complain about it only when the process enters the terminal stage, which is characterized by pronounced heart failure. The characteristic symptoms here are shortness of breath and edema.
Diagnosis of cardiomyopathy
To make a diagnosis of cardiomyopathy, the patient will undergo the following diagnostics:
- The doctor should ask the patient in detail whether his family members have heart disease, whether there were suddenly deceased relatives (especially at a young age). Carry out a thorough examination, listen to heart sounds, since the number of murmurs and frequency can unequivocally show the type of cardiac pathology.
- To exclude other pathology of the heart, it is required to do a biochemical blood test (blood electrolyte composition, markers of myocardial necrosis, lipid spectrum, serum glucose).
- Particular attention should be paid to indicators reflecting the functional state of the liver and kidneys, to make general clinical studies of urine and blood.
- Chest x-rays can show signs of enlargement of the left side of the heart in most patients, suggesting overload. But in some cases, the pathology on the x-ray may be completely absent.
- All patients with suspected cardiomyopathy should have an ECG. Ambulatory Holter monitoring is sometimes added to assess the effect nervous system and detect cardiac arrhythmias.
- An obligatory method for diagnosing cardiomyopathy is ultrasound.
- Patients who are to undergo surgery must undergo magnetic resonance imaging. It has a more powerful resolution than EchoCG, with its help you can see pathological changes and evaluate the structural features of the heart.
Independently, no patient will be able to make out which of the many types of cardiomyopathy he has. Only an experienced cardiologist can cope with such a task.
He will have to differentiate diseases that also lead to an increase in the left heart:
- myocardial hypertrophy caused by arterial hypertension;
- aortic stenosis;
- genetic pathologies;
- "sports" heart;
- amyloidosis.
To exclude genetic syndromes and diseases, consultation with a specialist in genetic disorders will be required. In cases high blood pressure in the output sections of the left ventricle, pronounced thickening of the wall of the left cardiac section, inefficiency drug therapy consultation with a cardiac surgeon is required. You will also need to consult an arrhythmologist.
Treatment of cardiomyopathy
The treatment of cardiomyopathy is a long and complex process, during which the patient must strictly follow all the instructions of his attending physician. It is aimed at restoring the proper functioning of the myocardium and maintaining its work at the required level. Treatment of this disease can take place through drug therapy, but may also include surgery.
Very important for the recovery process is the role of the patient himself, on which a successful outcome ultimately depends. We are talking about giving up bad habits (smoking and alcohol), and overweight patients will have to constantly diet, because the lower the body weight, the less stress falls on the heart, the more stable it works.
Medical therapy
Drugs for the treatment of cardiomyopathy are different. So, with dilated cardiomyopathy, it is necessary to fight, first of all, with heart failure and prevent the occurrence of possible complications. The patient needs to lower the level of blood pressure, so he is shown drugs - ACE inhibitors, such as captopril and enalapril. Small doses of beta-blockers (metaprolol) are also given. It is desirable to introduce an antioxidant and an alpha-beta blocker, such as carvedilol, into the course of therapy. Also, recommendations for cardiomyopathy regarding heart failure relate to the use of diuretics.
The goal of therapy in hypertrophic cardiomyopathy is aimed at improving the contractile activity of the left ventricle. Such patients are usually prescribed verapamil or disopyramide. To prevent the development of arrhythmias, beta-blockers are prescribed.
Restrictive cardiomyopathy is the most difficult to treat because it most often appears only in the terminal stage, so there are no reliable therapeutic methods for it.
Surgery
The question is how to treat cardiomyopathy if drug treatment is not successful.
- People with dilated cardiomyopathy are often offered a donor heart transplant.
- In the case of the hypertrophic variety of the disease, it has recently been preferred to implant pacemakers.
- The situation is worst with the restrictive form, since heart transplantation is often ineffective, since relapses often occur in the transplanted organ.
Several specific techniques have been developed for the treatment of secondary lesions. For example, bloodletting is done for hemochromatosis, and corticosteroids are prescribed for sarcoidosis.
Folk methods of treatment
Traditional medicine suggests that patients with cardiomyopathy improve their condition with a decoction of motherwort, a mixture of lily of the valley flowers, mint leaves, fennel seeds, valerian root, and infusion of flax seeds.
Complications of cardiomyopathy
The consequences of cardiomyopathy can be expressed in the following complications:
- Heart failure. With cardiomyopathy, blood flow from the left ventricle decreases, which causes the phenomenon of heart failure.
- valve dysfunction. An enlarged left ventricle can obstruct the flow of blood through the heart valves, causing backflow and making the heart beat less efficiently.
- Edema. In the lungs, tissues of the legs and abdomen with cardiomyopathy, fluid may accumulate due to the insufficient ability of the heart muscle to pump blood.
- Arrhythmias (abnormal heart rhythms). Changes in the structure of the myocardium and pressure in the heart chambers contribute to the distortion of the heart rhythm.
- Sudden cardiac arrest is the extreme case when cardiomyopathy causes death.
- Embolism. Stasis (combination) of blood in the left ventricle can cause the formation of blood clots, which, once in the bloodstream, can cut off blood flow to any organs and cause a heart attack, stroke of the brain or any other organ.
Prognosis for cardiomyopathy
Cardiomyopathy prognosis may vary, depending on various factors:
- how strictly the patient will adhere to all appointments and recommendations of the doctor;
- how severe were the symptoms of the disease at the time of its discovery.
Unfortunately, there is no effective prevention of cardiomyopathy. However, only pathology at the genetic level cannot be prevented in any way.
The least likely to get cardiomyopathy are those who lead an active lifestyle with proper nutrition and dosed physical activity. You must completely stop smoking and alcohol abuse.
If the pathology has arisen against the background of any disease, then it must be controlled by regularly undergoing examinations and strictly following the prescriptions of doctors.
Disability in cardiomyopathy
Possible disability with cardiomyopathy, the criteria for which is:
- presence of risk factors for sudden death;
- variant and form of the course of the disease;
- the severity of comorbidities;
- effectiveness of therapy;
- severity of complications;
- profession, education and qualifications of the patient, features of the character and working conditions.
Patients with cardiomyopathy receive group III disability if:
- there is a slowly progressive DCMP, HF 1st. in the absence of syncope and mild arrhythmias;
- progressive course of HCM, HF 1-IIA st., the presence of restrictions on the ability to self-service, movement, labor activity, the absence of risk factors for sudden death; if, with an asymptomatic course, there are contraindications to the previous profession, and there is no possibility of employment according to the conclusion of the CEC of the LPU.
II group of disability receive patients with:
- progressive course of cardiomyopathy with persistent disorders of the functioning of the cardiovascular system (HF IIB stage, with significant conduction and rhythm disturbances), with limited ability to move, self-care, work, learning - stage II, the presence of risk factors for sudden death;
- sometimes patients are allowed to work at home in special conditions, taking into account professional skills.
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Cardiomyopathy(Greek kardia heart + mys, myos muscle + pathos suffering, disease) - a group of heart diseases, common to which is selective primary myocardial damage of unknown etiology, pathogenetically not associated with inflammation, tumor, coronary insufficiency, arterial hypertension; manifested by cardiomegaly, heart failure and cardiac arrhythmias.
Myocardial damage in cardiomyopathy is characterized mainly by such pathological processes as dystrophy and sclerosis, which, due to the ambiguity of the origin, are, as it were, primary (idiopathic). According to the definition of K., they are opposed to myocarditis, heart tumors and all secondary myocardial lesions (in particular, with coronary heart disease, vasculitis, hypertension and symptomatic forms of arterial hypertension, heart defects, pulmonary heart, systemic diseases, including diffuse diseases connective tissue), as well as myocardial dystrophies of known etiology. Establishing the etiology and clarifying the pathogenesis of any disease related to cardiomyopathies would help distinguish it from this group into a number of known diseases or their outcomes, or into an independent nosological form.
In medical literature, especially foreign, sometimes instead of the term "myocardial dystrophy" the term "cardiomyopathy" is used, using it to refer to secondary non-isolated myocardial lesions of known etiology (for example, alcoholic cardiomyopathy), which is not recommended.
Classification. Cardiomyopathy include several forms of heart disease. There are two approaches to the classification of cardiomyopathies. The first of them involves the characterization of the anatomical changes in the heart underlying cardiomegaly - the expansion of the cavities (dilatation) of the heart or the thickening of its walls, incl. due to hypertrophy; the second is a characteristic of intracardiac hemodynamic disorders in the form of either obstruction of the outflow of blood through the outflow tract of the ventricle (obstruction) or a sharp limitation of heart extensibility in diastole (restriction). The most common subdivision of cardiomyopathies into the following main forms ( rice. one ):
I. Dilated cardiomyopathy (congestive, or congestive, K.); characterized by a sharp increase in the volume of the cavities of the heart due to dilatation with relatively thin walls (the ratio of the thickness of the wall of the ventricle to the volume of its cavity is much lower than normal).
II. Hypertrophic cardiomyopathy: 1) diffuse, or symmetrical, hypertrophic K. - hypertrophy of the interventricular septum and walls of the left (very rarely right) ventricle, referred to as idiopathic myocardial hypertrophy, or as non-obstructive hypertrophic K.; characterized by a significant increase in the thickness of the walls of the ventricle and its relationship to the volume of its cavity; 2) asymmetric myocardial hypertrophy; manifestations of the disease depend on the localization of the process; a) hypertrophy predominantly of the upper (basal) part of the interventricular septum (isolated or in combination with hypertrophy of the anterior lateral wall of the left ventricle), leading to obstruction of the outflow tract of the ventricle; this form is called obstructive hypertrophic cardiomyopathy, or idiopathic hypertrophic subaortic stenosis; b) hypertrophy of the predominantly apical part of the left ventricle; it is designated as apical hypertrophic K. (the phenomenon of obstruction at this form of a cardiomyopathy is absent).
III. Restrictive cardiomyopathy is a form that essentially combines endomyocardial fibrosis and Loeffler's eosinophilic fibroplastic endocarditis; characterized by a significant decrease in the diastolic volume of the ventricles due to the rigidity of their walls with a sharp limitation of extensibility in diastole, which is manifested by cardiac disorders resembling those in cardiac amyloidosis, constrictive pericarditis.
In addition to the above main classification, a number of authors use a more detailed division of hypertrophic cardiomyopathy according to the localization of hypertrophy, classify K. according to the features and severity of clinical manifestations and course. Some progress in studying the etiology and pathogenesis of dilated cardiomyopathy is encouraging with the prospect of isolating this form from the K. group in the near future; the validity of the allocation of the restrictive form is discussed (in the USSR, this form of cardiomyopathy is practically not found).
Etiology and pathogenesis. Dilated cardiomyopathy until the 60s of the 20th century. was considered in the framework of Abramov-Fiedler's idiopathic myocarditis. Many researchers have shown the relationship of the disease with viral infections caused, for example, by Coxsackie group B viruses, influenza, herpes simplex, ECHO viruses. In favor of the etiological role of Coxsackie viruses is evidenced by a higher than in control group, the frequency of detection in patients with dilated K. in elevated titers of antibodies to these viruses, especially to type B viruses, (according to Yu.I. Novikov et al., in 81.1% of patients), which corresponds to the frequency of detection of such antibodies in patients, who underwent serologically verified Coxsackie's myocarditis. The assumption about the viral nature of this form of cardiomyopathy is indirectly confirmed by some data on its pathogenesis, indicating changes in the reactions of antiviral immunity. So, in a number of patients with dilated K., paradoxical immune reactions to a banal viral infection, increased titers of complement components, usually activated by infectious agents, were detected. The role of certain haplotypes of HLA histocompatibility antigens in the development of a number of pathoimmune diseases is known, therefore, data on the predominance of the HLA-A3 / HLA-A9 haplotype among patients with this form of cardiomyopathy (HLA-A3 imbalance is associated with a defect in natural killers, which play an important role in antiviral protection ) confirm the involvement of immune disorders in the pathogenesis of dilated cardiomyopathy. These and other features of the immune status of patients with dilated K., together with data on the possible viral etiology of the disease, became the basis of the immune hypothesis of its pathogenesis, which is supported by many researchers. According to it, viruses that damage cardiomyocytes also induce violations of humoral and cellular immunity (in this case, the appearance of cytotoxic T-lymphocytes is of great importance), which determines the protracted course of myocarditis and the features of its morphological expression. Pathogenetic involvement of immune disorders in the development of the disease is not excluded even in the absence of its connection with myocarditis. It has been shown, for example, that approximately in half of the cases of dilated cardiomyopathy in the plasma of patients, the titer of complement C3a is increased, which can cause non-inflammatory damage to blood vessels with an increase in the permeability of their walls, microthrombosis and microcirculation disorders, which can cause degenerative changes in the myocardium and take part in thrombosis (thromboembolic complications in patients with a high titer of S3 were determined more often). Other hypotheses suggest the development of dilated K. without the determining participation of pathoimmune mechanisms. One of them, supported by experimental data, corresponds to the idea of dilated cardiomyopathy as a rare outcome of severe diffuse myocarditis, after which the remaining cardiomyocytes, under conditions of chronic intense compensatory hyperfunction, undergo hypertrophy and degeneration with the development of fibrous tissue; thickening of the membranes of cardiomyocytes, their separation by dense collagen fibers disrupt the metabolism of cells with the intercellular space, which contributes to the progression of dystrophy and violations of the contractile function of the myocardium, as well as conduction and heart rhythm. Along with the considered prerequisites for the possible identification of dilated cardiomyopathy with immunopathological myocarditis or with the outcome of viral myocarditis, it is also possible that it develops as a primary dystrophic process (with secondary inflammatory reactions to necrobiotic processes in the myocardium), for example, neurogenic myocardial dystrophy due to viral damage to heart neuron cells, described with this disease.
Hypertrophic K. in about 1/3 of patients is characterized by signs of a hereditary disease with an autosomal dominant type of inheritance. The prevailing opinion is that this form of cardiomyopathy is caused by a genetic defect in the formation and functioning of myofibrils. In the pathogenesis of hypertrophic K., an important role is played, apparently, by disturbances in energy metabolism in the heart muscle, which cannot be explained by a decrease in perfusion of the hypertrophied myocardium, which is found in some patients while maintaining the patency of the coronary arteries and unchanged diastolic pressure in the ventricles. It was shown that under normal perfusion, the rate of extraction of free fatty acids by the myocardium is reduced by more than 2 times in hypertrophic cardiomyopathy, while this is not observed with dilated cardiomyopathy, despite a decrease in perfusion and accumulation of fatty acids in the myocardium. It is possible that the primary deficiency of energy production in the myocardium underlies the increase in the number of mitochondria in cardiomyocytes (as in compensatory myocardial hypertrophy). Additional studies require the assumption of a relationship between hypertrophic cardiomyopathy and disturbances in the hormonal regulation of metabolism in the myocardium, in particular, with excessive realization of the effect of catecholamines and somatotropic hormone on cardiomyocytes.
Restrictive K. was initially considered as a polyetiological disease associated in some cases with the outcome of Leffler's eosinophilic fibroplastic endocarditis (see. Leffler syndromes). At the same time, in the pathogenesis of the disease, decisive importance was attached to the toxic effect on the endocardium and myocardium of specific proteins released from eosinophils during their degranulation. Accordingly, protozoal infections accompanied by eosinophilia were primarily assumed as etiological factors, which is confirmed by the predominant distribution of restrictive cardiomyopathy in tropical countries, where the incidence of protozoal infections is higher. However, the study of myocardial lesions in hypereosinophilia shows that their outcomes usually correspond to a dilated rather than a restrictive type of cardiohemodynamic disorders, and in many cases the disease is more correctly attributed to eosinophilic vasculitis, and not to the group cardiomyopathy. In cases of so-called idiopathic restrictive cardiomyopathy, not associated with eosinophilia, one cannot ignore the fact that endomyocardial fibrosis in itself is not a primary pathological process; it is seen as a reactive process in response to endothelial stress, in which smooth muscle cells produce elastin and collagen in large quantities.
The pathogenesis of hemodynamic disorders in cardiomyopathies, it reflects the features of cardiohemodynamic disorders characteristic of each of the main forms of K. In dilated cardiomyopathy, systolic heart failure is leading, characterized by a significant decrease in stroke volume due to a sharp decrease in ejection fraction, an increase in the final systolic and diastolic volumes of the left ventricle and an increase in the end diastolic pressure in it . The latter determines the early appearance of blood stagnation in the lungs, the development of secondary hypertension of the pulmonary circulation, which, with significant dilatation of the left ventricle, is aggravated by regurgitation of blood into the left atrium (due to relative insufficiency of the mitral valve). In connection with pulmonary hypertension, end-diastolic pressure in the right ventricle increases, it dilates (often with the formation of relative tricuspid insufficiency), and stagnation develops in the veins of the systemic circulation. As myocardial fibrosis progresses, the walls of the heart become less elastic; this leads to the addition of diastolic insufficiency, which increases refractoriness to the treatment of circulatory disorders.
In diffuse (non-obstructive) hypertrophic K., the relaxation of the left ventricle in the diastole phase is initially disturbed, which exacerbates the lack of energy supply to the heart muscle, which causes the development of heart failure and the formation of various cardiac arrhythmias, often determining the main clinical manifestations of the disease, and in some cases, death.
Specific for obstructive hypertrophic cardiomyopathy are pathological conditions of intracardiac hemodynamics, manifested by the picture of subaortic stenosis. The latter is formed due to the protrusion into the cavity of the left ventricle of hypertrophied sections of the interventricular septum and the anterolateral wall (the so-called two-chamber ventricle of the hourglass type). However, even before the stage of significant deformation of the ventricular cavity, systolic obstruction of the outflow of blood into the aorta occurs due to pathological deflection of the anterior leaflet of the mitral valve, which is facilitated by abnormal attachment and thickening of its papillary muscle. In the late phase of systolic expulsion, the anterior leaflet of the mitral valve almost touches the hypertrophied interventricular septum, significantly narrowing the outflow tract. Subaortic stenosis is expressed by the appearance of a pressure gradient between the cavity of the left ventricle and the initial part of the aorta, and with a two-chamber left ventricle - between the distal and proximal chambers. The pressure gradient is proportional to the degree of subaortic stenosis, which determines the severity of manifestations and the course of the disease.
At the heart of hemodynamic disturbances in restrictive K. is the limitation of diastolic stretching and filling of the ventricles with blood, in connection with which venous stasis is formed and cardiac output is reduced.
Pathological Anatomy. In all forms of cardiomyopathy, significant changes in the heart are found. However, in diffuse myocardial damage, they are not specific enough; in such cases, the interpretation of the detected changes and their classification as manifestations of cardiomyopathy are based on a combination of clinical data and the results of pathomorphological (including ultrastructural and histochemical) examination of the heart.
Dilated K. differs from other forms by a sharp expansion of all cavities of the heart, accompanied by signs of severe dystrophy and interstitial myocardial fibrosis. The so-called dilatational triad is considered characteristic: dilatation of the ventricles, coronary arteries and microvessels of the heart. The heart is large and spherical. The myocardium is flabby, dull, with visible layers of connective tissue. The ventricular endocardium is slightly thickened, parietal thrombi are often found. Myocytolysis, eosinophilia of cardiomyocytes, lymphohistiocytic infiltrates of subacute and chronic type are determined microscopically, and the nature of the infiltration does not differ significantly from that in myocarditis. Muscle fibers in most cases are oriented correctly, their nuclei are hyperchromic, which is typical for hypertrophy, but the diameter of myofibrils is not increased due to significant stretching of muscle fibers. The disorganization of the latter can be represented by their interlacing or alternation of narrow longitudinal and wide transverse bundles. According to some data, the proportion of binuclear myofibrils (reflecting the processes of hypertrophy due to amitosis) in dilated cardiomyopathy is almost 2 times lower than normal, and almost 3 times lower than with adequate compensatory hypertrophy of the left ventricle. In cardiomyocytes, there are foci of destruction and lysis of myofibrils, dystrophic changes in mitochondria and hyperplasia of the smallest of them, which is characteristic of energy deficiency in the myocardium; signs of calcium and magnesium metabolism disorders are revealed. The processes of dystrophy with cytolysis of cardiomyocytes sometimes capture large areas of the myocardium, spread to the cells of the conduction system of the heart and vascular endothelium, are accompanied by the growth of connective tissue, replacing dead cells and forming widespread fields of cardiosclerosis. In general, these processes, in combination with lymphohistiocytic infiltration of the myocardium, correspond to the picture of the so-called idiopathic myocarditis.
Diffuse (symmetrical) hypertrophy of the left ventricular myocardium is characterized by a uniform thickening of its walls, a significant increase in the ratio of the mass of the left ventricle to the total mass of the heart. The cavity of the left ventricle is usually reduced. The atrial cavities are dilated. With asymmetric hypertrophic K., a local thickening of the interventricular septum (total or partial), one of the walls or the apex of the heart is determined. Obstructive hypertrophic K. is characterized by a deformation of the cavity of the left ventricle (up to an hourglass configuration) due to local thickening within the upper 2/3 of the interventricular septum and in the region of the anterolateral wall of the left ventricle. Usually, this form of cardiomyopathy shows higher insertion, thickening, and shortening of the papillary muscle of the anterior mitral leaflet. The histological picture is heterogeneous and only in some cases has signs of a characteristic disorganization of muscle fibers (their chaotic orientation with eddies around the connective tissue layers), which was considered specific for asymmetric forms of hypertrophic K. In this form, there are two types of pathomorphological changes. The first is characterized by nuclear dystrophy and pronounced foci of collagen sclerosis with moderate hypertrophy of muscle fibers. The second type is characterized by significant hypertrophy of muscle fibers in the absence of sclerosis. In muscle fibers and in the structures of the connective tissue, signs of dystrophy and reactive compensatory changes are histochemically determined. As with other types of muscle fiber hypertrophy, the glycogen content in them is increased. In the myocardium, the content of connective tissue is increased, an excess of mitochondria, their swelling, partial atrophy or complete disappearance of cristae, a decrease in the number of myofibrils, which reflects the complex nature of damage to cardiomyocytes, but not the specifics of the disease.
Restrictive K. is morphologically manifested by predominant thickening of the endocardium due to excessive development of connective tissue in it and in the subendocardial layer of the myocardium. In the case of parietal fibroblastic endocarditis, granulation tissue is also detected, while the inflammatory infiltrate contains mainly eosinophils. Changes predominate in the region of the apex of the heart and in the posterior wall of the left ventricle, sometimes involving the posterior leaflet of the mitral valve. Myocardial fibers are oriented correctly, hypertrophied. In the subendocardial layers, foci or fields of dusty calcification are often found. In the study of the ultrastructure of the myocardium, degeneration of myofibrils, pronounced vacuolization of the membranes are noted.
Clinical picture and course. In almost all forms of cardiomyopathy, complaints appear and patients go to the doctor when changes in the heart are already significantly pronounced and in most cases there is cardiomegaly. Complaints as the reason for the first visit to the doctor are more often noted with dilated K. and idiopathic hypertrophic subaortic stenosis.
Dilated To. is more often first detected at the age of 30-40 years, although its development is possible in children and the elderly. There is a slowly and rapidly progressive course of dilated cardiomyopathy. With a slow course, the disease manifests itself for a long time only with cardiomegaly and ECG changes, symptoms develop after a few years. heart failure. With a rapidly progressive course, severe circulatory disorders occur several months after the first complaints appear and lead to death in the next 2-5 years. The basis of the clinical manifestations of the disease are signs of increasing heart failure, cardiac arrhythmias, among which most often (approximately in 2/3 patients) a permanent form is detected atrial fibrillation, as well as occasional thromboembolism(more often pulmonary arteries, less often arteries of the brain, kidneys, limbs), during life they are recognized in approximately 70% of patients. Patients complain of severe general weakness, fatigue, shortness of breath and palpitations during physical exertion, the tolerance to which, with a rapidly progressing course of the disease, decreases very quickly (every week), which makes the doctor assume a severe pathology of the heart, primarily myocarditis, effusion pericarditis or dilated K The use of cardiac glycosides is usually ineffective or ineffective. Seizures appear relatively early cardiac asthma, nocturia. As circulatory disorders progress, peripheral edema, ascites occur, the liver enlarges, and the cervical veins swell. The pulse on the peripheral arteries is small, usually arrhythmic, frequent; pulse pressure is reduced. The apex beat of the heart is diffuse, weakened; percussion is determined by a significant expansion of the boundaries of the heart in all directions. Auscultation often reveals a gallop rhythm, I tone is weakened, a systolic murmur is heard, characteristic of mitral and (and) tricuspid insufficiency. During auscultation of the lungs, hard breathing, moist fine bubbling rales, localized in low-lying areas (depending on the position of the patient's body), are determined. Radiologically, a large spherical heart is detected, the shadow of which covers a significant area of the lung fields (cardiothoracic index is more than 0.6), the amplitude of the pulsation along the entire contour of the heart shadow is weakened; in the lungs reveal signs of venous congestion. Various rhythm disturbances are noted on the ECG - more often atrial fibrillation and (or) ventricular extrasystole (in about 1/3 of patients), atrioventricular block, bundle branch block, signs of left atrial hypertrophy, decreased voltage of the main teeth of the ventricular complex, sometimes pathological Q waves or QS, creating a picture of post-infarction changes, rarely - displacement of the RST segment, inversion of the T wave. In the blood, the albumin-globulin coefficient may be reduced, polycythemia, hypokalemia, and sometimes increased bilirubinemia are observed.
Hypertrophic K. occurs in people of any age, incl. often in children. Clinical manifestations and course are determined by the predominant localization of hypertrophic changes in the myocardium, on which disturbances in intracardiac hemodynamics and the likelihood of severe cardiac arrhythmias depend. The apical form of asymmetric hypertrophic cardiomyopathy, which is more often detected after accidental detection on the ECG of negative deep T waves in all chest leads; the most severe course is characteristic of idiopathic hypertrophic subaortic stenosis.
With diffuse hypertrophic cardiomyopathy, many patients have no complaints for a long time, although there are already ECG changes and an increase in heart size has been established. Complaints of shortness of breath, palpitations, fatigue, sometimes chest pains are late manifestations of the disease, preceding the development of progressive heart failure. First, as a rule, various cardiac arrhythmias occur (they are less characteristic with predominant total hypertrophy of the interventricular septum), incl. paroxysms of ventricular tachycardia (may be accompanied by fainting), atrial fibrillation, ventricular extrasystole. Over time, cardiac arrhythmias progress and often become the cause of death of patients even before the development of severe heart failure. With percussion, palpation of the apex beat of the heart, radiological and instrumental studies of the heart, significant hypertrophy of the left ventricle is determined; in some patients, a systolic murmur is heard at the base of the heart, which does not have characteristic features; in the later stages of the disease, a systolic murmur characteristic of relative mitral insufficiency may be noted.
With idiopathic hypertrophic subaortic stenosis, patients complain relatively early about shortness of breath, pain in the heart, dizziness, fainting, palpitations (with a feeling of an increase in both the frequency and strength of heart beats), which are not always clearly associated with physical activity. Pain in the region of the heart in most cases is stopped by nitroglycerin. Paroxysmal rhythm disorders, extrasystoles are often noted. Obstructive hypertrophic K., which is first detected in people over 60 years of age, is characterized by an oligosymptomatic course. Some authors, depending on the prevalence of certain symptoms, suggest distinguishing various variants of the disease - pseudocoronary (with angina pectoris), rheumatic (with a predominance of signs characteristic of heart disease), dystonic (with dizziness, weakness, palpitations, etc.). When examining the heart, attention is paid to its significant displacement to the left and increased apex beat (sometimes it is defined as bifurcated); in some cases, at the base of the heart, a low-frequency oscillation of the chest (left atrial click) is palpated. The volume of both heart sounds is preserved; for 1 tone after a pause, i.e. in the mesosystolic period, a systolic murmur is heard, usually most pronounced in the third or fourth intercostal space immediately to the left of the sternum, but also heard at the apex and at the Botkin point, the murmur is rarely carried out on carotid arteries; characteristic increase in the intensity of the noise after taking nitroglycerin, with a sharp change in body position from horizontal to vertical, in the Valsalva test. In some cases, a soft diastolic murmur is determined due to incomplete closure of the aortic valve cusps during deformation of the aortic lumen due to sharp hypertrophy of the interventricular septum. On the carotid, femoral, less clearly on the radial arteries, pulse dicrotia can be detected; with mildly pronounced subaortic stenosis, pulse dicrotia can only be determined on a sphygmogram. The course of idiopathic hypertrophic subaortic stenosis largely depends on the presence and severity of cardiac arrhythmias, which, as in diffuse hypertrophic cardiomyopathy, can cause the death of patients even in the early stages of the disease. Congenital anomalies of the conducting system of the heart, often combined with obstructive K., contribute to the emergence of arrhythmias; with this form of cardiomyopathy, more often than with others, the syndrome of premature excitation of the ventricles is determined. In some cases, especially with atrial fibrillation, the course of obstructive K. is complicated by parietal thrombosis of the left cavities of the heart with thromboembolism of the arteries of the systemic circulation.
On the ECG in both forms of hypertrophic K, various changes are noted, reflecting primarily the degree and predominant localization of myocardial hypertrophy, up to 8 types of ECG changes are described (with this form of cardiomyopathy), as well as rhythm and conduction disturbances. Along with an increase in the voltage of the main teeth of the ventricular complex, pathological Q waves are most often determined in leads I, aVL, V 4 -V 6 (with predominant hypertrophy of the interventricular septum, often in leads II, III, aVF) and QS in leads V 1 -V 3. In some patients, an incomplete or complete blockade of one of the legs of the bundle of His is found (the right one, mainly with isolated hypertrophy of the interventricular septum). The shift of the RST segment, depression and inversion of the T wave are the same as in compensatory myocardial hypertrophy.
Angiocardiography and probing of the heart cavities reveal changes in the volume of the left ventricle and pressure in it, characteristic of each variant of hypertrophic K., in different phases of the cardiac cycle: the final systolic and diastolic volumes are reduced, the ejection fraction is increased (sometimes up to 80% of the diastolic volume), at the end of systole in patients with idiopathic hypertrophic subaortic stenosis, a two-chamber ventricle may form; between the chambers (or the cavity of the ventricle and the initial part of the aorta), a pressure gradient is determined, reflecting the degree of stenosis.
Clinical manifestations of restrictive cardiomyopathy are characterized by the predominance of symptoms of right ventricular heart failure with a sharp increase in central and peripheral venous pressure. There is evidence of frequent formation in this form of relative tricuspid insufficiency. In all patients, an increase in the liver is noted, in about half it is combined with an increase in the spleen. For this form To. early development of peripheral hypostases, ascites is characteristic. An X-ray examination of the heart determines cardiomegaly and a significant decrease in the amplitude of the pulsations of the walls of the ventricles; sharply enlarged atria. The ECG shows a low voltage of the teeth, signs of overload of the left atrium and the right heart, often a blockade of the right leg of the His bundle, and disturbances in the anterior ventricular conduction.
Diagnosis. Cardiomyopathy should be suspected in all cases where cardiomegaly is detected, especially in combination with arrhythmias and signs of heart failure, if their origin cannot be reliably explained by the presence of known diseases in the patient leading to such changes in the heart.
At the stage of outpatient examination of the patient, the diagnosis of cardiomyopathy can only be presumptive. To confirm it, a targeted examination is required in a specialized cardiological hospital or diagnostic center, where special methods studies (echocardiography in different modes, immunological biochemical, histological methods, etc.).
Of all the forms of K., the diagnosis of only local asymmetric hypertrophic cardiomyopathy is based on characteristic changes in the shape and function of the left heart, detected by instrumental methods. With K. with diffuse myocardial damage, there are no specific symptoms, therefore, the diagnosis of dilated, diffuse hypertrophic and restrictive cardiomyopathy is established only by excluding all other heart diseases similar in clinical manifestations and substantiated using data from general clinical, laboratory and instrumental studies, including, if necessary, a study myocardial biopsy.
Dilated cardiomyopathy is recognized with the greatest difficulty due to the lack of specific clinical manifestations and due to the fact that this form of K. has to be differentiated from many diseases: congenital heart defects And acquired heart defects; myocardial dystrophy with thyrotoxicosis (see Goiter diffuse toxic), various exogenous intoxications (including with chronic alcoholism, alcohol abuse) anemia, long-term use of glucocorticoids and other hormonal drugs, drugs; painless form coronary heart disease; vascular cor pulmonale(including in connection with the repeated thromboembolism of the pulmonary arteries); changes in the heart hemochromatosis, glycogenosis and other metabolic disorders, diffuse connective tissue diseases; myocarditis of various etiologies and with unknown etiology.
In the absence of sufficient grounds for the diagnosis of any of the listed diseases, dilated K. is most likely to be assumed if there is a triad of clinical manifestations: progressive heart failure tolerant to cardiac glycosides, cardiac arrhythmias and conduction disturbances, and thromboembolic complications. The diagnosis is confirmed when a small spherical heart is found on a chest X-ray (Fig. rice. 2 ), a decrease in the amplitude of the pulsation of its walls and signs of stagnation in the pulmonary circulation. Consider that the disease often develops at the age of 30-40 years; in most cases, it has a rapidly progressive course, from a variety of rhythm disturbances detected in almost all patients, a constant form of atrial fibrillation (in about 2/3 of patients) and ventricular extrasystole (in about 1/3 of patients) are most characteristic of dilated cardiomyopathy.
ECG changes due to their diversity and non-specificity for confirming the diagnosis of dilated K. are not significant, but in some cases their nature is determined by those diseases with which it is necessary to carry out a differential diagnosis in the first place, for example, coronary heart disease (in the presence of a pathological Q wave and other heart attack-like or ECG changes characteristic of focal cardiosclerosis), cor pulmonale (with predominance of ECG signs of right ventricular hypertrophy), myocarditis (with complex rhythm and conduction disturbances, atrioventricular blockade), heart defects (if there are ECG signs combined hypertrophy of both ventricles and left atrium).
Significant, although not decisive, are the data of echocardiography, in which the following typical signs are revealed ( rice. 3 ): a sharp expansion of the cavities of the left and right ventricles of the heart, as well as the cavity of the left atrium; hypokinesia of the posterior wall of the left ventricle and interventricular septum; different types asynergy of the myocardium of the left ventricle; an increase in the distance between the anterior leaflet of the mitral valve and the interventricular septum (mitral-septal separation). With the help of echocardiography, valvular heart disease and effusion pericarditis are also excluded, with which it is necessary to differentiate dilated K. during the initial examination of a patient with severe heart failure.
The clinical diagnosis of dilated cardiomyopathy is considered a relative indication for myocardial biopsy. However, the nonspecificity of the detected changes, even with the totality of data from pathomorphological, histochemical and ultrastructural studies (which requires at least 5 biopsy specimens), determines the low frequency of relatively reliable confirmation of the diagnosis (in about half of the cases), and negative data do not exclude the presence of the disease. Absolutely reliable differential diagnosis of dilated K. and myocarditis on the basis of laboratory data and the results of a study of myocardial biopsies is currently, according to many researchers, impossible. The diagnosis of dilated cardiomyopathy is preferable if the progressive increase in heart failure is not accompanied by changes in biochemical parameters indicating inflammation in the myocardium, the appearance of antibodies to the myocardium, and, at the beginning of the disease, also an increase in the titer of antibodies to Coxsackie viruses and other viruses that can cause myocarditis.
Diffuse hypertrophic cardiomyopathy is established when signs of cardiac hypertrophy are detected (according to palpation, percussion, x-ray studies, ECG changes) by excluding arterial hypertension and heart defects, which can also be causes of hypertrophy. In persons with normal blood pressure and no murmurs over the heart, the diagnosis of non-obstructive hypertrophic K. should be assumed immediately, especially in cases where Q waves are determined on the ECG in lead I, aVL, V 4 -V 6, and QS in leads V 1 -V 2 .
With a clinically justified assumption of the presence of diffuse hypertrophic cardiomyopathy, a study of the heart using two-dimensional echocardiography is necessary, which in many cases is sufficient to confirm the clinical diagnosis, because allows you to simultaneously exclude organic damage to the heart valves and detect signs characteristic of diffuse hypertrophic cardiomyopathy. The latter include thickening of the posterior wall of the left ventricle up to 1.6-2 cm(sometimes more) or predominantly the entire interventricular septum with its hypokinesia.
Differential diagnosis is difficult if there is a suspicion of congenital heart disease and large vessels of the chest cavity (especially in children) and in the initial stages of diffuse hypertrophic K. in persons with possible compensatory myocardial hypertrophy (in the presence of arterial hypertension, intense sports loads, etc.) . Congenital heart disease is confirmed or excluded by contrast cardioangiography and measurement of pressure in the cavities of the heart and large vessels by probing them. Compensatory myocardial hypertrophy in patients with hypertrophic disease and with intense sports loads is proportional to the degree and duration of the increase in blood pressure or the intensity of the load, combined with an increase in the diastolic volume of the left ventricle; the thickness of its posterior wall in athletes usually does not exceed 11 mm, and the ratio of the mass of the left ventricle to the final diastolic volume is usually not higher than 1.2 g/ml.
Asymmetric hypertrophic cardiomyopathy in the case of localization of the process in the region of the apex of the left ventricle, it can be suspected by accidental detection of ECG changes, of which the appearance of deep (giant) negative T waves in all chest leads is most characteristic.
Obstructive hypertrophic K. suggest in patients with clinical manifestations resembling aortic stenosis (see. Acquired heart defects), but with a number of features. Depending on the leading clinical manifestations, differential diagnosis is most often carried out with ischemic disease heart disease and rheumatic heart disease, with a positive diagnosis of asymmetric hypertrophic cardiomyopathy being critical. The most characteristic signs of subaortic stenosis according to J.F. Goodwin are a dicrotic pulse with normal blood pressure; late systolic murmur in the third - fourth intercostal space to the left of the sternum, at the apex, and Botkin's point; left atrial click, determined by palpation of the heart in the region of the base. The listed triad of signs is noted with a pronounced degree of obstruction, therefore, in the early stages of the disease, the most attention should be paid to the features of systolic murmur, which distinguishes it from murmur in aortic stenosis (primary localization in the third - fourth intercostal space to the left of the sternum, frequent absence of conduction to the vessels of the neck, increase in Valsalva test after taking nitroglycerin). Signs of pronounced hypertrophy of the left ventricle according to ECG and X-ray examination significantly help to establish the diagnosis.
The main method for diagnosing all variants of asymmetric hypertrophic K. is a two-dimensional echocardiography. With idiopathic hypertrophic subaortic stenosis on echocardiograms ( rice. 4 ) are determined by the small diastolic size of the cavity of the left ventricle (3.5-4 cm), hypokinesia of the interventricular septum, thickening of its basal part with an increase in the ratio of its thickness to the thickness of the posterior wall of the left ventricle. There are also characteristic changes in the movement of the leaflets of the mitral and aortic valves: pathological deflection during systole of the anterior leaflet of the mitral valve towards the interventricular septum until it comes into contact with it; decrease in the rate of early diastolic decline of the anterior leaflet; during echolocation of the aortic valve in the middle of systole, a “break” is determined with the formation of a pattern in the form of the letter M on the echocardiogram, and not a “box”. In apical cardiomyopathy, a local thickening of the apex is detected, extending to the apical part of the interventricular septum and part of the wall of the left ventricle ( rice. five ).
In rare cases, the echocardiographic picture is not informative enough for a reliable diagnosis of asymmetric hypertrophic K., in particular, the apical one. In this case, magnetic resonance imaging of the heart has some advantages, with the help of which the dimensions and configuration of the cavities of the left ventricle and left atrium are more accurately determined, and asymmetric hypertrophy of its walls is more clearly revealed. To diagnose and assess the degree of subaortic stenosis, in some cases (for example, when establishing indications for surgical treatment), sounding of the left ventricle is performed to measure the pressure gradient between it and the initial part of the aorta.
Very rarely there is a need for differential diagnosis of asymmetric hypertrophic cardiomyopathy with a tumor of the heart. In such cases, a myocardial biopsy is indicated.
Restrictive cardiomyopathy it is expected in patients with cardiomegaly with low voltage ECG waves and total heart failure, accompanied by a significant increase in venous pressure, hepatomegaly, ascites, peripheral edema, if constrictive pericarditis and heart defects are excluded. The restrictive form differs from dilated K. by a decrease in the diastolic volume of the ventricles (with a pronounced increase in the atrial cavities) and a significant decrease in the rate of filling the ventricles with blood during diastole. However, the establishment of the restriction phenomenon itself is not enough for the diagnosis of restrictive cardiomyopathy. Since this form practically does not occur in the USSR, careful exclusion of other diseases is necessary, primarily amyloidosis heart, which may require a heart biopsy.
Treatment . Before the development of severe circulatory failure, all patients with K. are treated mainly on an outpatient basis under the constant (dispensary) supervision of a cardiologist and a local doctor, although the initial selection of therapy is usually carried out in a hospital where a diagnosis of cardiomyopathy is made. Indications for emergency hospitalization occur with intractable paroxysms of tachycardia, atrial fibrillation, the appearance of dangerous variants of ventricular extrasystoles(type "R on T", group), development pulmonary edema, thromboembolism of the arteries of the small or large circulation. Patients with severe circulatory insufficiency are subject to scheduled periodic hospitalization, when the correction of the ongoing treatment is possible only under the control of the dynamics of heart function indicators or the biochemical composition of the blood, which are promptly studied only in a hospital.
Etiological and pathogenetic therapy To. is not developed. The main is symptomatic treatment, aimed mainly at eliminating or reducing the degree of heart failure and correcting cardiac arrhythmias, and in case of thromboembolic complications or their threat, it also includes the use of anticoagulants and platelet deaggregants.
With dilated cardiomyopathy, conservative treatment of heart failure is carried out against the background of maximum restriction of physical activity; prescribed for a long period (3-4 weeks) bed rest, followed by a gradual transition to a minimum self-service regimen, only when hemodynamics stabilize in this mode, the patient is allowed to walk short distances (for example, to a bench near the house) at a slow pace, avoiding climbing stairs. To improve the metabolism of proteins in the myocardium, a diet with a high content of animal protein and anabolic hormones, such as methandrostenolone (nerobol), 5 mg 2 times a day before meals for a month, then 5 mg 1 time per day for 1-3 months. followed by a break for 2-3 months. Cardiac glycosides (usually celanide or digoxin orally) are used with caution - the initial daily dose should not exceed 1/3 of the usual maintenance dose (in relation to the generally accepted average therapeutic dose); if there are no arrhythmogenic effects, then the dose is gradually increased; treatment with glycosides is continued only if there are signs of a positive effect. More often, cardiac glycosides are not effective, therefore, preference is given to non-glycoside cardiotonic agents such as dobutamine, amrinone, prenalterol. The last drug side effect which is an increase in the activity of renin, angiotensin II and aldosterone in the blood, should be administered simultaneously with captopril. The main in the treatment of heart failure in patients with dilated K. is the use of peripheral vasodilators in various combinations (for example, apressin and nitrosorbide) and the correct selection of drugs and doses. diuretics. This takes into account the dynamics of the electrolyte composition of the blood, as well as the possibility of developing conditions that contribute to thrombosis (activation of the blood coagulation system, atrial tachyarrhythmia, etc.), which can be prevented by prescribing heparin. The experience of a number of clinicians shows that the combined use of cardiac glycosides, diuretics, peripheral vasodilators and heparin against the background of limited physical activity can reduce the severity of manifestations of heart failure and somewhat prolong the life of patients. mainly in hypertrophic cardiomyopathy), in particular cardioselective metoprolol (starting at 12.5 mg and bring it up to 100 mg per day). However, in all cases there is a period of almost complete refractoriness to drug therapy, and the only way to save the patient is a heart transplant, and in case of significant pulmonary hypertension (for example, due to repeated pulmonary embolism) - transplantation of the lung-heart complex.
With hypertrophic K. in the case of the development of heart failure, treatment is based on the same principles of symptomatic therapy as in dilated cardiomyopathy, however, anabolic hormones are contraindicated, and cardiac glycosides are used with even greater caution, not only because of the danger of their arrhythmogenic effect, but also in connection with a possible additional decrease under their influence of the volume of the left ventricle. The main place in the treatment of patients with hypertrophic K. is occupied by antiarrhythmic therapy, which includes the correction of established rhythm disturbances and the prevention of sudden death from ventricular fibrillation. Of great importance is the limitation of physical stress, the connection with which in patients with hypertrophic K. accounts for about 80% of cases of sudden death (i.e., about 2 times more than the frequency of such a connection in people with compensatory myocardial hypertrophy in a number of diseases). It is believed that one of the causes of sudden death may be limited distensibility of the left ventricle, therefore, β-adrenergic blockers (for example, propranolol) and calcium antagonists (for example, verapamil), which improve ventricular relaxation during diastole, must be included in the treatment complex. However, with ventricular arrhythmias that threaten ventricular fibrillation, these drugs do not prevent sudden death, and in such cases it is advisable to prescribe amiodarone (cordarone), for example, according to the following scheme: 1st week - 600 mg per day, 2nd week - 400 mg per day, followed by a decrease in the frequency of taking the drug (up to 600 mg in Week). Other methods are also used to stop detectable cardiac arrhythmias. antiarrhythmic drugs; there is evidence of a positive effect of the parenteral use of a coenzyme drug complex, including pyridoxal phosphate, cobamamide and phosphaden.
In idiopathic hypertrophic subaortic stenosis, surgical attempts are made to reduce the intracardiac pressure gradient. Septal myotomy (resection of the hypertrophied part of the interventricular septum) and mitral valve replacement are performed.
Forecast. With a long asymptomatic course of cardiomyopathy, the prognosis for the life and working capacity of the patient is uncertain, because the course may change under the influence of an intercurrent disease or physical exertion, and sudden death is not excluded at any stage of the disease. With a rapidly progressive course of dilated and restrictive K., as well as from the moment of increasing arrhythmias or heart failure with hypertrophic cardiomyopathy, the prognosis is generally unfavorable. The life expectancy of patients with dilated K. from the moment of diagnosis is on average about 7 years; in about half of the cases, death occurs from progressive heart failure and thromboembolic complications, in the remaining cases, sudden death is noted. The risk of sudden death in dilated cardiomyopathy increases with a decrease in the left ventricular ejection fraction, an increase in the number of paired ventricular extrasystoles per day, and with atrial fibrillation. Heart transplantation in patients with dilated K. in many cases significantly prolongs their life: patients with surgery more than 10 years old were followed up. Sudden death predominates as an outcome of hypertrophic cardiomyopathy. Surgical treatment of idiopathic hypertrophic subaortic stenosis improves the condition in about 3 out of 4 patients who underwent surgery, but mortality due to the operation itself remains high (about one in six patients die), and in about half of cases of death it occurs during the operation.
Prevention cardiomyopathy has not been developed.
Bibliography: Mukharlyamov N.M. and Zatushevsky I.F. Subaortic stenosis (idiopathic hypertrophic), p. 138, Chisinau, 1982; Novikov Yu.I., Stulova M.A. and Lavrova I. K. About the role of Coxsackie viruses of group B in the etiology of dilated cardiomyopathy, Ter. arch., vol. 61, no. 11, p. 97, 1989; Ryabykina G.V. etc. Changes in the electrocardiogram in hypertrophic cardiomnopathy, ibid., No. 4, p. 54; Sumarokov A.V. and Moiseev V.S. Clinical cardiology, p. 167, M., 1986; Khazanov E.A., Lyapon D.O. and Burchakin Yu.A. Cardiomyopathies (classification clinic, diagnosis, treatment), Klin. honey., t. 64, No. 7, p. 11, 1986, bibliogr.