Cardiomyopathy is a group of diseases that affect the heart muscle.[1]Early on there may be few or no symptoms. Others may have shortness of breath, feel tired, or have swelling of the legs due to heart failure. An irregular heart beat may occur as well as fainting.[2] Those affected are at an increased risk of sudden cardiac death.[3]

Types of cardiomyopathy include hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular dysplasia, and broken heart syndrome. In hypertrophic cardiomyopathy the heart muscle enlarges and thickens. In dilated cardiomyopathy the ventricles enlarge and weaken. In restrictive cardiomyopathy the ventricle stiffens.[4]

The cause is frequently unknown. Hypertrophic cardiomyopathy is often and dilated cardiomyopathy in a third of cases, is inherited from a person’s parents. Dilated cardiomyopathy may also result from alcohol, heavy metals, coronary heart disease, cocaine use, and viral infections. Restrictive cardiomyopathy may be caused by amyloidosis, hemochromatosis, and some cancer treatments.[5] Broken heart syndrome is caused by extreme emotional or physical stress.[4]

Treatment depends on the type of cardiomyopathy and the degree of symptoms. Treatments may include lifestyle changes, medications, or surgery.[6] In 2013 cardiomyopathy and myocarditis affected 7.9 million people.[7] Hypertrophic cardiomyopathy affects about 1 in 500 people while dilated cardiomyopathy affects 1 in 2,500.[4][8] They resulted in 443,000 deaths up from 294,000 in 1990.[9]Arrhythmogenic right ventricular dysplasia is more common in young people.