LAUSR

Hypertrophic cardiomyopathy (HCM) is a relatively common inherited myocardial disorder, once regarded largely untreatable with ominous prognosis, and most visibly as a common cause of sudden death (SD) in the young. Over the last several years HCM has been transformed into a contemporary treatable disease with management options that significantly alter clinical course. With penetration of implantable cardioverter-defibrillators (ICD) into the HCM patient population, a new paradigm has emerged with primary prevention device therapy reliably terminating potentially lethal ventricular tachyarrhythmias (3-4%/year), largely responsible for a >10-fold decrease in disease-related mortality to 0.5%/year, independent of age. A guideline-based clinical risk stratification algorithm has evolved, including variables identified with cardiac magnetic resonance. One or more risk markers judged major and relevant within a patient's clinical profile can be considered sufficient to recommend a primary prevention implant (associated with a measure of physician judgment and shared decision-making). ICD decisions using the individual risk marker strategy have been associated with 95% sensitivity for identifying patients who subsequently experienced appropriate ICD therapy, albeit often delayed substantially for >5 or >10 years after implant, but without heart failure deterioration or death following device intervention. A rigid mathematically-derived statistical risk model proposed by ESC is associated with low sensitivity (i.e., 33%) for predicting SD events. Introduction of prophylactically implanted ICDs to HCM 20 years ago has significantly altered the clinical course and landscape of this disease. SD prevention has reduced HCM mortality significantly making preservation of life and potential for normal longevity a reality for most HCM patients.