Risk Stratification for Sudden Death in Hypertrophic Cardiomyopathy

Abstract

Early studies suggested that hypertrophic cardiomyopathy (HCM), an inherited and primary disease of cardiac muscle characterized by a thickening of the left ventricular (LV) walls, was a relatively uncommon but malignant disorder. The annual mortality rates were reported to be 2–4% in adults and 6% in adolescents and children, the majority of deaths being sudden. Recently it has been found that HCM is, in fact, more common than originally assumed, with a prevalence estimated from echocardiographic population screening of 0.2%. It is also now clear that HCM is much more benign, with an annual mortality rate in large unselected non-referred series of approximately 1.5%. More than half of these deaths are sudden while the remainder are largely caused by heart failure and stroke [1]–[3]. This relatively low incidence creates a challenge for risk stratification. Furthermore, most individuals with HCM are asymptomatic and the first manifestation may be sudden cardiac death (SCD), related to ventricular arrhythmia with potential triggers including ischemia, outflow obstruction, and atrial fibrillation.