Sudden cardiac death in hypertrophic cardiomyopathy.

Introduction Hypertrophic cardiomyopathy (HCM) is a common disorder of cardiac muscle associated with sudden cardiac death (SCD). HCM is defined by increased left ventricular wall thickness or mass, in the absence of abnormal loading conditions to account for the observed abnormality. In most adults, the disease is inherited as an autosomal dominant trait and is caused by mutations in cardiac sarcomere protein genes. Histologically, HCM is characterized by myocardial disarray, fibrosis, and small vessel disease. Macroscopically, the hypertrophy is typically asymmetrical and 25% of patients have resting left ventricular outflow tract obstruction (LVOTO). SCD in HCM is caused mainly by ventricular arrhythmias that can be effectively treated by implantable cardioverter defibrillator (ICD) therapy. Identification of patients at high risk is a cornerstone of management and research during the past 4 decades has recognized a number of phenotypic characteristics that can be used to identify those patients who might benefit from an ICD.