Snapshot A 16-year-old boy presents to his pediatrician for syncope. In the past few months, he had syncopal episodes when he played football, soccer, and sprinting. His family history includes sudden cardiac death in several relatives. An echocardiogram shows marked hypertrophy and abnormal systolic anterior leaflet motion of the mitral valve. (Hypertrophic cardiomyopathy) Introduction Clinical definition cardiomyopathies intrinsically affect the myocardium, leading to systolic or diastolic dysfunction these do not include changes in the myocardium secondary to hypertension, coronary artery disease, or valvular disorders types of cardiomyopathies dilated cardiomyopathy (most common) restrictive/infiltrative cardiomyopathy hypertrophic cardiomyopathy (obstructive vs non-obstructive) Cardiomyopathies Dilated Restrictive/Infiltrative Hypertrophic Etiology ABCD Alcohol abuse Beriberi (wet) Coxsackie B viral myocarditis Chronic Cocaine use Chagas disease Doxorubicin toxicity Hemochromatosis Sarcoidosis Titin mutation Peripartum cardiomyopathy Radiation therapy Loffler endocarditis (with endomyocardial fibrosis and eosinophilic infiltrate) Endocardial fibroelastosis (in children) Amyloidosis Sarcoidosis Scleroderma Troponin mutation Hemochromatosis Familial (most common) autosomal dominant mutations in sarcomere proteins (β-myosin heavy chain = myosin binding protein C > tropomyosin = troponin I/C - in order of frequency of mutations) Idiopathic Pathology Systolic dysfunction from ↓ contractility and↓ ejection fraction Eccentric hypertrophy (sarcomeres added in series) Stiff myocardium causesdiastolic dysfunction Preserved left ventricular systolic function Diastolic dysfunction from ↓ compliance of left ventricle Septal hypertrophy Majority of cases are obstructive (hypertrophic obstructive cardiomyopathy) Concentric hypertrophy (sarcomeres added in parallel) Clinical presentation Congestive heart failure S3 sound Systolic murmur Progressive heart failure Sudden cardiac death S4 sound (and others can present with S3) + Kussmaul sign Syncope with activity Sudden cardiac death (especially in young athletes) S4 sound Systolic murmur without radiation ↑ with decrease in preload or afterload, e.g., Valsalva, standing up, diuretics, nitroglycerin ↓ with increase in preload or afterload, e.g., hand grip and squatting Diagnostic studies Chest radiography ballooning of heart Echocardiogram dilated ventricles and ↓ ejection fraction Electrocardiogram bundle branch block Chest radiography cardiomegaly and pulmonary congestion Echocardiogram thickening of all structures diastolic dysfunction Endomyocardial biopsy the most accurate test for etiology Electrocardiogram may have low voltages Echocardiography normal ejection fraction hypertrophy mitral regurgitation decreased end systolic volume and end diastolic volume Electrocardiogram left ventricular hypertrophy Histology tangled and disoriented myofibrils Treatment Angiotensin-converting enzyme inhibitors β-blockers Spironolactone Automatic implantable cardioverter/defibrillator Biventricular pacemaker Treat underlying condition Diuretics Heart transplant Avoid athletic activities β-blockers Non-dihydropyridine calcium channel blockers Implantable cardioverter/defibrillator