Cardiomyopathy refers to several diseases that affect the myocardium (heart muscle) and are associated with mechanical and/or electrical dysfunction. In cardiomyopathy, abnormal heart function results from weakness or structural changes in the myocardium.
After coronary artery disease (CAD) and hypertension (high blood pressure), dilated cardiomyopathy is the third most common cause of heart failure in the United States.
In hypertrophic cardiomyopathy (HCM), the myocardium is thickened. As a result, it becomes difficult for the heart to pump blood. Nearly one-half of deaths due to HCM occur during or after physical activity. Sudden death occurs due to lethal heart rhythm disturbances (ventricular fibrillation and ventricular tachycardia). It is the most common cause of sudden cardiac death in athletes as a result of structural heart changes in response to intense training.