Donald Teare’s original pathological description of hypertrophic cardiomyopathy (HCM) was based on eight young adults, seven of whom died suddenly.1 Almost 40 years later, the identification of individuals at risk for sudden death and its effective prevention remains the major therapeutic challenge in this disorder. While HCM is, in most series, the most common cause of sudden death in asymptomatic young adults, adolescents and athletes,2 the annual risk of sudden death for patients with HCM is not certain. Annual incidences of 1–2% in adults and 4–6% in children and adolescents have been reported from tertiary centres.2 Recent natural history studies from non-referral centres however indicate a better prognosis.3 This in part reflects referral bias as well as increased recognition of the disease. HCM has been considered a rare disease with adverse prognosis; however, emerging data from a number of studies suggest that it is a common disease (∼ 1 in 500; estimated 150 000 sufferers in the UK),4 with relatively good prognosis. The challenge therefore remains to identify the small group who are at risk of major complications particularly sudden death.