Cardiomyopathies are non-vascular, non-valvular cardiomyopathies with cardiac dysfunction and predominantly myocardial lesions. Cardiomyopathies can be divided into two major categories according to whether they have a clear etiology: primary cardiomyopathies, which have an unknown etiology. The other category is secondary cardiomyopathies with a clear etiology. Primary cardiomyopathy is divided into dilated cardiomyopathy, hypertrophic cardiomyopathy and restrictive cardiomyopathy according to pathophysiological characteristics.
Diagnosis
1, dilated cardiomyopathy (DCM)
(1) Clinical manifestations: cardiac insufficiency; cardiac rhythm disturbance; due to the slow blood flow, the formation of attached wall thrombus in the heart cavity, dislodged to form body or pulmonary circulation embolism. It can be divided into adult type and infant type.
(2) Physical examination: heart enlargement; first heart sound is diminished, some children have gallop rhythm, and systolic murmur of relative mitral valve insufficiency may appear in the mitral valve area.
(3) Ancillary examinations.
①X-ray shows generalized cardiac enlargement, mostly in the left ventricle, with diminished heart beat and significant pulmonary stasis.
(2) EkG shows left ventricular hypertrophy, ST segment drop, flat or inverted T wave, premature ventricular beats, and sinus tachycardia.
The echocardiogram showed enlarged left atrium and left ventricle with small mitral valve diastolic opening, forming a “large heart cavity with small opening” image and reduced ventricular wall activity.
2, hypertrophic cardiomyopathy (HCM)
(1) Clinical manifestations: cardiac insufficiency; myocardial ischemia: chest pain, dyspnea, syncope, palpitations, sudden death.
(2) Physical examination: In some cases, the heart is enlarged, the apical beats are shifted downward to the left and may be elevated or double beats, and systolic jet-like murmurs of grade 3-6 are heard between the 3-4 intercostal spaces at the left edge of the sternum and in the apical region, with reverse splitting of the second heart sound (P2 in front and A2 in the back).
(3) Ancillary examinations.
①X-ray shows mild to moderate enlargement of the heart with a spherical appearance, diminished heart beat, and pulmonary stasis.
(2) EKG shows enlarged atria and left ventricle with abnormal Q waves, mostly in leads II, III, aVF and V3, V5, resembling myocardial infarction.
③Echocardiography: the ratio of septum to posterior left ventricular wall thickness ≥1.5, left ventricular outflow tract stenosis, such as asymmetric hypertrophy of the septum, so the disease is also called asymmetric septal hypertrophy (ASH) or idiopathic hypertrophic subaortic stenosis (IHSS).
④Cardiogram: The left ventricular cavity is lingual in systolic stenosis in the lateral view, and the right ventriculogram shows the hypertrophic septum occupying toward the right ventricular outflow tract.
3.Restricted cardiomyopathy (RCM)
(1) Clinical manifestations: early stage may be asymptomatic, or only mild dizziness, weakness or palpitations after activity. Late manifestations of diastolic dysfunction such as dyspnea, jugular venous anger, hepatomegaly, ascites, lower limb edema, etc. appear.
(2) Physical examination: enlarged heart borders, weakened apical beats, accelerated heart rhythm, gallop rhythm, systolic murmur in the left atrioventricular valve area or third and fourth heart sounds are heard. There may be an increase in venous pressure during inspiration (Kussmaul’s sign).
(3) Ancillary examinations.
(1) X-ray shows mild to moderate enlargement of the heart, with enlargement of both atria, especially the right atrium, predominant. Pulmonary stasis, a small amount of pleural effusion and new pericardial effusion.
EKG shows widened P waves with cut marks, showing enlargement of both right and left atria; right ventricular hypertrophy, right bundle branch conduction block, ST segment downward shift and T wave hypotonic inversion, etc., as well as arrhythmia.
The echocardiogram showed thickening of the endocardial echocardiographic reflection, thickening of the left ventricular wall, narrowing of the ventricular cavity and significant enlargement of the left and right atria, and occlusion of the apex of the heart.
Treatment
1.Dilated cardiomyopathy
(1) Digoxin, 0.02-0.04 mg/kg, apply its 1/4 amount per day, divided into two doses, take 6 days to stop 1 day, long-term until 1 year after the heart size returns to normal.
(2) Angiotensin-converting enzyme inhibitors, such as Kepone or Enalapril, in small doses for long-term use.
(3) Intermittent application of diuretics.
(4) For intractable heart failure, add dobutamine, dobutamine; milrinone; combined tachyphylaxis; and fructose 1,6-diphosphate (FDP) intravenously for 10 to 14 days.
(5) After the symptoms of heart failure improve, long-term low-dose medoxin (betalactam) can be taken, or choose calcium antagonists, such as cardiac pain (nifedipine), thiodiazepine (Tenelheart), etc.
(6) Adrenocorticosteroids: For children with cardiogenic shock, heart failure and high atrioventricular block, hormone therapy can be added for about six months. It is also recommended to apply the immunosuppressant azathioprine at 2 mg/kg daily.
(7) Children with advanced disease can be treated with heart transplantation.
2. Hypertrophic cardiomyopathy
(1) Limit the child’s strenuous activities.
(2) Avoid digitalis, isoprenaline and tachyphylaxis, etc.
(3) β-blockers: Jinan, 1~2mg/kg per day, can be gradually increased to 3~4mg/kg, divided into 3 doses; Medoxinan, etc.
(4) Calcium antagonists: isoptin, 4-6mg/kg per day, divided into 3 doses; thiodiazepine can be 1.5-3mg/kg per day, long-term use.
(5) Ventricular arrhythmia: Amiodarone, 8-12mg/kg per day in 3 doses.
(6) Heart failure: diuretics, vasodilators, small doses of insulin and digoxin combined.
(7) Severe obstruction of the left ventricular outflow tract, with pressure step difference at rest exceeding 9.3 kPa (70 mmHg), interventricular diaphragm dissection or removal of hypertrophic myocardial tissue of the left ventricular outflow tract can be performed.
3. Restrictive cardiomyopathy
(1) Treatment for possible causes, such as eosinophilic endocarditis, can be treated with prednisone.
(2) control of heart failure, digitalis drugs do not work well, such as atrial fibrillation combined with rapid ventricular rate can be used digoxin; ascites, edema can be used diuretics.
(3) Children with significant cardiac ischemia and (or) syncope may be considered for placement of a buried cardioverter-defibrillator.
(4) Endocardial resection or heart valve repair or replacement is available abroad.