Cardiomyopathy is an umbrella term for a group of diseases that effect the cardiac muscle, in which the walls of the heart chamber(s) become stretched, thickened or stiff. Cardiomyopathy affects the structure of the heart and consequently negatively impacts its ability to pump blood efficiently. Major symptoms include but are not limited to sudden cardiac arrest, swelling of legs and feet, arrhythmia, dyspnea, fatigue and syncope. Common Cardiomyopathies include hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). Others include restrictive cardiomyopathy, arrhythmogenic right ventricular dysplasia and takotsubo cardiomyopathy. Cardiomyopathy tends to run in families and some types of Cardiomyopathy are largely genetic such as DCM. In the USA half of the 750,000 cases of DCM are familial.