Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is a condition in which the muscle tissue of the heart becomes abnormally thickened without an obvious external cause, most often affecting the wall between the ventricles and the ventricles themselves. This thickening reduces the heart's pumping efficiency and can disrupt its electrical conduction. Many people have no symptoms, but others experience shortness of breath from impaired ventricular filling, chest pain from reduced coronary blood flow, palpitations, lightheadedness and fainting, with serious complications including heart failure, irregular heartbeats and sudden cardiac death. The condition is predominantly inherited in an autosomal dominant pattern, usually caused by a mutation in one of at least nine genes that encode proteins of the heart's sarcomere; about forty to sixty percent of patients have an identified mutation, with the beta myosin heavy chain gene and the cardiac myosin binding protein C gene each accounting for around forty percent of identified cases. Secondary causes include Fabry disease and Friedreich's ataxia, and it must be distinguished from other causes of heart enlargement such as athlete's heart and high blood pressure.