Cardiac disease

Introduction to cardiomyopathy Cardiomyopathy (DDM) is a group of lesions that are progressively impaired by cardiac function due to structural changes in the subventricular chamber (ie, the ventricle) and impaired myocardial wall function. Its clinical manifestations include heart enlargement, arrhythmia, embolism and heart failure. The cause is generally related to viral infection, autoimmune reaction, genetics, drug poisoning and metabolic abnormalities. According to pathology, it can be divided into dilated cardiomyopathy, hypertrophic cardiomyopathy and restrictive cardiomyopathy. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of infection: non-infectious Complications: Infective endocarditis, sudden death, arrhythmia

Cause of cardiomyopathy

Dilated cardiomyopathy (20%):

Dilated cardiomyopathy may be associated with certain factors of the virus. Myocardial damage caused by abnormal metabolism of bacterial drug poisoning is related, and viral myocarditis is considered to be the main cause. Sustained viral infection damage to myocardial tissue, autoimmunity including cells, autoantibodies or cytokine-mediated myocardial damage can lead to or induce dilated cardiomyopathy. In addition, perinatal, alcoholism, anticancer drugs, myocardial energy metabolism disorders and neurohormone receptor abnormalities can also cause this disease.

Hypertrophic cardiomyopathy (20%):

May be related to autosomal dominant inheritance, about 1/3 of the family history, cardiac myosin heavy chain and cardiac troponin T gene mutation are the main pathogenic factors. In addition, abnormal metabolism of catecholamines, abnormal regulation of intracellular calcium, high blood pressure, high-intensity exercise, etc. can be used as a promoting factor for the onset of this disease.

Restricted cardiomyopathy (20%):

Endocardial myocardial fibrosis, myocardial stiffness and ventricular diastolic filling are characterized by obstruction. The onset is slow, and early symptoms such as fever, fatigue, dizziness, and shortness of breath may occur. Late heart failure occurs. Atrial fibrillation is also more common, with partial visceral embolism. More common in tropical and temperate regions, China has only sporadic cases.

Arrhythmogenic right ventricular cardiomyopathy (20%):

Arrhythmogenic right ventricular cardiomyopathy, formerly known as arrhythmogenic right ventricular dysplasia, characterized by right ventricular myocardium replaced by progressive fibrous adipose tissue, clinical manifestations of right ventricular enlargement, arrhythmia and sudden death. In the 1995 report of the WHO/ISFC Working Group Expert Committee on the definition and classification of cardiomyopathy, ARVD/C was listed as a fourth type of primary cardiomyopathy along with dilated cardiomyopathy, hypertrophic cardiomyopathy, and restrictive cardiomyopathy.

Cardiomyopathy prevention

Because there is no clear understanding of the etiology and pathogenesis of this disease, there is currently no effective preventive measure. In the existing preventive measures, because the complications of this disease are more common, it is actively treated and taken. Effective measures to prevent complications are key.

Cardiomyopathy complications Complications Infective endocarditis sudden cardiac arrhythmia

Common complications of cardiomyopathy include arrhythmia, heart failure, embolism, infective endocarditis, and sudden death:

1. Infective endocarditis and sudden death occur mostly in patients with cardiac hypertrophy.

2, embolism occurs in patients with myocardial fibrosis and decreased contractility, combined with atrial fibrillation, long-term immobilization or diuretics.

3. Sudden death is a common fatal complication.

Symptoms of cardiomyopathy Common symptoms Dyspnea, cardiac hypertrophy, palpitations, arrhythmia, dizziness, neonatal heart failure, shortness of breath, fatigue, heart rate, flu-like symptoms

The first symptoms of the disease are usually shortness of breath after activity and fatigue, which is caused by heart pumping dysfunction (heart failure). When cardiomyopathy is caused by infection, the patient's first symptom can be sudden fever and flu-like illness. Symptoms, regardless of the cause, the patient's heart rate increases, accompanied by a drop in blood pressure or normal, fluid retention in the thighs and abdomen, and fluid accumulation in the lungs, due to an enlarged heart causing heart valve opening, dysfunction, Therefore, it often leads to a certain amount of blood reflux in the heart (mitral and tricuspid). In this case, heart murmur can often be heard by means of a stethoscope, and myocardial damage and myocardial tension or stretching can often lead to arrhythmia ( Too fast or too slow).

Cardiomyopathy examination

1, ECG examination

Dilated cardiomyopathy: ECG examination is based on ST-segment depression, T-wave low-level or inversion, and a few pathological Q waves.

Hypertrophic cardiomyopathy: ECG often shows left ventricular hypertrophy and ST-T changes, some Q waves appear, atrioventricular block and bundle branch block are also more common.

Restrictive cardiomyopathy: ECG shows low voltage, atrial and ventricular hypertrophy, bundle branch block, ST-T changes and atrial fibrillation and other arrhythmias.

2, physical examination

Hypertrophic cardiomyopathy: the heart of the physical examination can be enlarged to the left, the anterior region of the heart can be heard and contracted, the late jet murmur, and the second heart sound often divides.

Restricted cardiomyopathy: The heart beat is weak, the heart sound is pure, and the second heart sound in the pulmonary valve area is hyperthyroidism. It can be heard in the diastolic period and the arrhythmia.

3, echocardiography

Dilated cardiomyopathy: showing expansion of the heart chamber, ventricular septum, posterior wall motion of the left ventricle is weakened, ejection fraction is reduced, and left and right ventricular outflow tract is enlarged.

Hypertrophic cardiomyopathy: Echocardiography is of great value in the diagnosis of this disease. It is characterized by ventricular septum and left ventricular wall hypertrophy. The ratio of the thickness of the two is greater than the normal 1.3:1, clinical manifestations, combined with echocardiography and ventricular angiography. Often diagnosed.

Restricted cardiomyopathy: Two-dimensional echocardiography revealed a narrow heart chamber, apical occlusion, endocardial thickening, and severe impairment of ventricular diastolic function.

4. Other:

Ventricular angiography showed that the ventricular cavity was reduced in hypertrophic cardiomyopathy, and the hypertrophic myocardium protruded into the ventricular cavity. In the examination of dilated cardiomyopathy, X-ray showed mild enlargement of the heart and partial endocardial calcification. shadow.

Diagnosis and diagnosis of cardiomyopathy

diagnosis

The diagnosis of the disease mainly depends on symptoms and physical examination. Sometimes it can show characteristic abnormalities on the electrocardiogram. Echocardiography and magnetic resonance can be used to confirm the diagnosis of the disease. If the diagnosis is still not confirmed, cardiac catheterization can be performed in the catheter. Endocardial myocardial biopsy can also be performed during the examination to obtain a definitive diagnosis and a clear cause.

Differential diagnosis

In the diagnosis of this disease, the following diseases should be identified:

1, rheumatic heart disease

Cardiomyopathy may also have systolic murmurs in the mitral or tricuspid valve area, but generally do not have diastolic murmurs, and are louder in heart failure, and reduce or disappear after heart failure control. Rheumatic heart disease is the opposite. Cardiomyopathy often has multiple heart chambers at the same time, not as good as rheumatic heart disease, left atrium, left ventricle or right ventricle. Ultrasound is helpful to distinguish.

2, pericardial effusion

When the cardiomyopathy is enlarged, the heart is weakened and the heart beat is weakened. It must be distinguished from the pericardial effusion. When the cardiomyopathy is apex, the apex beats to the left and the left, which is consistent with the left outer edge of the heart sounding boundary. The apical beat is often not obvious or in the heart during pericardial effusion. The medial left outer edge of the voiced sound circle, the systolic murmur of the mitral or tricuspid valve area, the ventricular hypertrophy on the electrocardiogram, the abnormal Q wave, various complicated arrhythmia, all indicate cardiomyopathy, and it is not difficult to distinguish the two by ultrasound. A large amount of liquid flat or dark area in the pericardium indicates pericardial effusion, and cardiac enlargement is a cardiomyopathy. It must be noted that there may be a small amount of pericardial effusion during cardiomyopathy, but it is not enough to cause cardiac tamponade or affect the heart. Signs and cardiac function are only the findings of ultrasound. The systolic time interval is abnormal in cardiomyopathy, and pericardium is normal.

3, hypertensive heart disease

Cardiomyopathy may have transient hypertension, but the diastolic blood pressure does not exceed 14.67 kPa (110 mmHg), and in acute heart failure, blood pressure drops after heart failure improves, unlike hypertensive heart disease, fundus, urine, kidney functioning normally.

4, coronary heart disease

Patients with middle-aged and above, if there is heart enlargement, arrhythmia or heart failure without other reasons, coronary heart disease and cardiomyopathy must be considered, and there are risk factors such as hypertension, hyperlipidemia or diabetes, and segmental abnormalities in wall motion. Conducive to the diagnosis of coronary heart disease, in recent years, coronary artery disease caused by long-term extensive ischemia and fibrosis of the heart, the development of cardiac dysfunction is called "ischemic cardiomyopathy", if there is no angina or myocardial infarction in the past, and Cardiomyopathy is difficult to distinguish, and then cardiomyopathy can also have pathological Q wave and angina pectoris, the identification must rely on coronary angiography.

5, congenital heart disease

Most have obvious signs, it is not difficult to distinguish, the tricuspid valve is deformed with tricuspid valve murmur, and there may be galloping, heartbeat weakening, right heart enlargement and failure, must be different from cardiomyopathy, but the symptoms of this disease appear In the early years, the left ventricle was not large, and the purpura was relatively high. Echocardiography could confirm the diagnosis.

6, secondary cardiomyopathy

Systemic diseases such as systemic lupus erythematosus, scleroderma, hemochromatosis, amyloidosis, glycogen accumulation, neuromuscular diseases, etc. have their primary disease manifestations can be distinguished, more important is the distinction between myocarditis, Acute myocarditis often occurs at the time of viral infection or soon after, the difference is not very difficult, if there is no clear history of acute myocarditis in chronic myocarditis, it is difficult to distinguish from cardiomyopathy. In fact, many dilated cardiomyopathy develop from myocarditis, that is, The so-called "myocarditis after cardiomyopathy".

In recent years, endocardial myocardial biopsy has been performed clinically. Specimens obtained from cardiac catheters with biopsy forceps for pathological and viral examinations can be used to find evidence of myocardial inflammation, but the current diagnostic criteria for histopathology and There are still some problems to be solved in removing artifacts.

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