Hypertrophic cardiomyopathy: diagnosis, risk stratification and treatment.

mon inherited cardiomyopathy, occurring in about 1 in 500 individuals. The first gene mutation for this condition was identified in a large French Canadian family cohort in 1989. Clinical presentation typically includes left ventricular hypertrophy in the absence of abnormal loading conditions, such as hypertension or aortic stenosis. Hypertrophic cardiomyopathy has come to public recognition in large part because of sudden cardiac death in a subset of young, otherwise healthy individuals with the condition. Depending on the severity and location of hypertrophy, dynamic obstruction of the left ventricular outflow tract can occur, and it may be quite limiting in some cases. Less widely appreciated sequelae of hypertrophic cardiomyopathy include atrial arrhythmia and consequent embolic phenomena, as well as progression to heart failure and, in some cases, requirement for cardiac transplant. Increasingly, the use of imaging and mutation analysis have made very early and preclinical genetic diagnosis possible. The same diagnostic advances are poised to contribute meaningfully to risk stratification (e.g., likelihood of sudden cardiac death). Given the frequency of hypertrophic cardiomyopathy and the development of additional diagnostic and prognostic strategies, practitioners require a reasonable evidence-based approach to diagnose, assess and treat this disease. In this review, we address these needs and identify areas of ongoing controversy. Evidence in this area comes from highly varied sources, including relatively large populations in retrospective cohort and population studies, as well as family-focused observational analyses (Box 1). These studies guide expert opinion and, in many cases, are the result of careful clinical observation of specialty care offered at select high-volume centres. Prospective randomized controlled trials are largely absent from the literature on hypertrophic cardiomyopathy.