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Cardiomyopathy is an anatomic and pathologic diagnosis associated with muscle or electrical dysfunction of the heart. Cardiomyopathies represent a heterogeneous group of diseases that often lead to progressive heart failure with significant morbidity and mortality. Cardiomyopathies may be primary (i.e., genetic, mixed, or acquired) or secondary (e.g., infiltrative, toxic, inflammatory). Major types include dilated cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy, and arrhythmogenic right ventricular cardiomyopathy. Although cardiomyopathy is asymptomatic in the early stages, symptoms are the same as those characteristically seen in any type of heart failure and may include shortness of breath, fatigue, cough, orthopnea, paroxysmal nocturnal dyspnea, and edema. Diagnostic studies include B-type natriuretic peptide levels, baseline serum chemistries, electrocardiography, and echocardiography. Treatment is targeted at relieving the symptoms of heart failure and reducing rates of heart failure-related hospitalization and mortality. Treatment options include pharmacotherapy, implantable cardioverter-defibrillators, cardiac resynchronization therapy, and heart transplantation. Recommended lifestyle changes include restricting alcohol consumption, losing weight, exercising, quitting smoking, and eating a low-sodium diet. (Am Fam Physician. 2009;79(9):778-784. Copyright © 2009 American Academy of Family Physicians.)
Cardiomyopathy is an anatomic and pathologic diagnosis associated with muscle or electrical dysfunction of the heart. The American Heart Association (AHA) defines cardiomyopathy as a heterogeneous group of diseases of the myocardium, usually with inappropriate ventricular hypertrophy or dilatation.1 There are various causes of cardiomyopathy, most of which are genetic. Cardiomyopathy may be confined to the heart or may be part of a generalized systemic disorder, often leading to cardiovascular death or progressive heart failure-related disability.1
Epidemiology
In 2006, the AHA classified cardiomyopathies as primary (i.e., genetic, mixed, or acquired) or secondary (e.g., infiltrative, toxic, inflammatory).1 The four major types are dilated cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy, and arrhythmogenic right ventricular cardiomyopathy (Table 1(1-9)).
Dilated cardiomyopathy, the most common form, affects five in 100,000 adults and 0.57 in 100,000 children.10,11 It is the third leading cause of heart failure in the United States behind coronary artery disease (CAD) and hypertension.1 Hypertrophic cardiomyopathy, the leading cause of sudden death in athletes, is an autosomal dominant disease with an incidence of one in 500 persons.1,12 Restrictive cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy are rare, and their diagnoses require a high index of suspicion.
Etiology
The causes of cardiomyopathies are varied (Table 2).1...