Introduction
Hypertrophic cardiomyopathy (HCM) is an inherited cardiac muscle disorder, transmitted predominantly in an autosomal dominant fashion with variable penetrance and an estimated prevalence of one in 500 in the western population.1 Myocardial hypertrophy most commonly affects the interventricular septum and may be associated with dynamic obstruction of the left ventricular outflow tract (LVOT),2 caused by systolic anterior motion (SAM) of the mitral valve leaflets. LVOT obstruction may occur at rest or only become apparent during physiological stress. Symptoms related to LVOT obstruction include dyspnoea, exertional chest pain, pre-
