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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: dilated, hypertrophic, and restrictive (see Fig. 1: Cardiomyopathies: Forms of cardiomyopathy. ) based on the pathologic features. The term ischemic cardiomyopathy refers to the dilated, poorly contracting myocardium that sometimes occurs in patients with severe coronary artery disease (with or without areas of infarction). Although it does not describe a primary myocardial disorder, the term remains in common use.
Manifestations of cardiomyopathies are usually those of heart failure and vary depending on whether there is systolic dysfunction, diastolic dysfunction, or both (see Heart Failure: Pathophysiology). Some cardiomyopathies may also cause chest pain, syncope, or sudden death.
Evaluation typically includes ECG and echocardiography and sometimes MRI. Some patients require endomyocardial biopsy (transvenous right ventricular or retrograde left ventricular). Other tests are done as needed to determine the cause. Treatment depends on the specific type and cause of cardiomyopathy (see Table 1: Cardiomyopathies: Diagnosis and Treatment of Cardiomyopathies ).
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Table 1
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| Diagnosis and Treatment of Cardiomyopathies |
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Feature or Method
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Dilated
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Hypertrophic
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Restrictive
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Pathophysiology
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Systolic dysfunction
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Diastolic dysfunction ± outflow obstruction
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Diastolic dysfunction
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Clinical findings
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LV and RV failure
Cardiomegaly
Functional AV valve regurgitation
S3 and S4
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Exertional dyspnea, angina, syncope, sudden death
Ejection ± mitral regurgitation murmurs, S4
Bifid carotid pulse with a brisk upstroke and rapid downstroke
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Exertional dyspnea and fatigue
LV ± RV failure
Functional AV valve regurgitation
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ECG
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Nonspecific ST- and T-wave abnormalities
Q waves ± BBB
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LV hypertrophy and ischemia
Deep septal Q waves
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LV hypertrophy or low voltage
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Echocardiography
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Dilated hypokinetic ventricles ± mural thrombus
Low EF and, frequently, functional AV valve regurgitation
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Hypertrophied ventricle ± mitral systolic anterior motion ± asymmetric hypertrophy ± LV gradient
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Increased wall thickness ± cavity obliteration
LV diastolic dysfunction
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X-ray
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Cardiomegaly
Pulmonary venous congestion
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No cardiomegaly
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No or mild cardiomegaly
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Hemodynamics
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Normal or high EDP, low EF, diffusely dilated hypokinetic ventricles ± AV valve regurgitation
Low CO
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High EDP, high EF ± outflow subvalvular gradient ± mitral regurgitation
Normal or low CO
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High EDP, dip and plateau diastolic LV pressure curve
Normal or low CO
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Prognosis
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20% mortality in first year, and about 10%/yr thereafter
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About 1% annual risk of sudden death
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70% 5-yr mortality
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Treatment
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Diuretics, ACE inhibitors, angiotensin II receptor blockers, β-blockers, spironolactone or eplerenone, digoxin, ICD, biventricular pacing, anticoagulants
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β-blockers ± verapamil ± disopyramide ± septal myotomy ± catheter alcohol ablation; AV pacing
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Phlebotomy for hemochromatosis
Endocardial resection
Hydroxyurea for hypereosinophilia
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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; ±
= with or without.
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Last full review/revision January 2010 by J. Malcolm O. Arnold, MD
Content last modified February 2012
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