A cardiomyopathy is a primary disorder of the heart muscle. It is distinct from structural cardiac disorders such as coronary artery disease, valvular disorders, and congenital heart disorders. Cardiomyopathies are divided into 3 main types based on the pathologic features (see figure Forms of Cardiomyopathy):
The term ischemic cardiomyopathy refers to the dilated, poorly contracting myocardium that can occur in patients with severe coronary artery disease (with or without areas of infarction). It is not classically considered to be in the above-listed categories because it does not describe a primary myocardial disorder.
Manifestations of cardiomyopathies are usually those of heart failure and vary depending on whether there is systolic dysfunction, diastolic dysfunction, or both. Some cardiomyopathies may also cause chest pain, syncope, arrhythmias, or sudden death.
Evaluation typically includes family history, blood tests, ECG, chest x-ray, echocardiography, and cardiac MRI. Some patients require endomyocardial biopsy. Other tests are done as needed to determine the cause. Treatment depends on the specific type and cause of cardiomyopathy (see table Diagnosis and Treatment of Cardiomyopathies).
Forms of Cardiomyopathy
Diagnosis and Treatment of Cardiomyopathies
Feature or Method | |||
|---|---|---|---|
Pathophysiology | Systolic dysfunction | Diastolic dysfunction ± outflow obstruction | Diastolic dysfunction |
Clinical findings | LV and RV failure, sudden death Cardiomegaly Functional AV valve regurgitation S3 and/or S4 | Exertional dyspnea, angina, syncope, sudden death Systolic murmur ± mitral regurgitation murmur, S4 Bifid carotid pulse with a brisk upstroke and rapid downstroke | Exertional dyspnea and fatigue LV ± RV failure Functional AV valve regurgitation |
ECG | Nonspecific ST- and T-wave abnormalities Q waves ± BBB | LV hypertrophy and ischemia Deep septal Q waves | LV hypertrophy or low QRS voltage |
Echocardiography | Dilated hypokinetic ventricles ± mural thrombus Low EF and, frequently, functional AV valve regurgitation | Hypertrophied ventricle, high, normal or low EF ± mitral systolic anterior motion ± asymmetric hypertrophy ± LV gradient | Increased wall thickness ± cavity obliteration LV diastolic dysfunction |
X-ray | Cardiomegaly Pulmonary venous congestion | No or mild cardiomegaly | No or mild cardiomegaly |
Hemodynamics | Normal or high EDP, low EF, diffusely dilated hypokinetic ventricles ± AV valve regurgitation Low CO | High EDP ± outflow subvalvular gradient ± mitral regurgitation Normal or low CO | High EDP, dip and plateau diastolic LV pressure curve Normal or low CO |
Prognosis | 20% mortality in first year, and about 10%/year thereafter | About 1% annual risk of sudden death | 70% 5-year mortality |
Treatment | Diuretics, ACE inhibitors, angiotensin II | Beta-blockers, ± | Phlebotomy for hemochromatosis Endocardial resection |
ACE = angiotensin-converting enzyme; ARNI = angiotensin II receptor blocker and neprilysin inhibitor; AV = atrioventricular; BBB = bundle branch block; CO = cardiac output; EDP = end-diastolic pressure; EF = ejection fraction; ICD = implantable cardioverter-defibrillator ; LV = left ventricular; RV = right ventricular; S3 = 3rd heart sound; S4 = 4th heart sound; SGLT2 = sodium glucose cotransporter 2 protein; ± = with or without. | |||
