Rowin EJ, et al. - Researchers investigated if patients with the most extreme expression of massive LV hypertrophy, an especially aggressive form of hypertrophic cardiomyopathy (HC), could have favorable long-term outcomes when treated with advanced treatment options available for HC. They identified 92 HC patients with extreme LV wall thickness (30-48 mm) and 1674 HC patients with less marked hypertrophy (13mm-29 mm) among 1766 consecutive HC patients presenting to Tufts HC Institute (2004 to 2015). Both of these patient groups were compared. An increased arrhythmic sudden death risk was observed in patients with the most extreme expression of HC, and prophylactic ICDs afforded reliable prevention of this risk. Surgical myectomy reversed progressive heart failure secondary to outflow obstruction. Overall, extended survival with good quality of life can be achieved with contemporary treatment interventions in young HC patients despite having extreme phenotypic expression.