Natural History of Untreated Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a primary disorder of the myocardium with a wide range of anatomic and physiologic forms. Up to 70 % of all HCM patients have either resting or provocable left ventricular outflow tract (LVOT) obstruction while others have predominantly non-obstructive forms. A small proportion of patients have apical hypertrophy which can lead to apical aneurysms. This condition affects people of all ages including the pediatric and adolescent population, as well as adults and the elderly. Although the majority of HCM patients have a relatively benign outcome, it is still the most common cause of death in young people, likely due to ventricular arrhythmias. Untreated HCM can lead to progressive symptoms due to diastolic dysfunction, LVOT obstruction, microvascular ischemia, and mitral regurgitation. A small percentage of HCM patients may develop end stage heart failure with impaired left ventricular systolic function. Stroke is another devastating outcome due to atrial fibrillation or thrombus formation in the setting of an apical aneurysm.