Management and outcomes of hypertrophic cardiomyopathy in young adults

BACKGROUND: Management of young adults with hypertrophic cardiomyopathy (HCM) is challenging. AIMS: To evaluate the profile of young adults (16-25 years) with HCM included in the French prospective HCM registry. METHODS: Patients were compared according to occurrence of major adverse cardiac events (MACE), comprising sudden cardiac death (SCD) events (implantable cardioverter defibrillator [ICD] discharge, SCD, sustained ventricular tachycardia), atrial fibrillation/embolic stroke, heart failure hospitalisation and unexplained syncope, at a mean follow-up of 4.4±2.2 years. RESULTS: At baseline, among 61 patients (20.5±3.0 years; 16 women, 26.2%), 13 (21.3%) had a prophylactic ICD, 24.6% a family history of SCD, 29.5% obstruction, 86.0% magnetic resonance imaging myocardial fibrosis, 11.8% abnormal exercise blood pressure and 52.8% a European Society of Cardiology (ESC) 5-year SCD score<4% (24.5%≥6%). At follow-up, 15 patients (24.6%; seven women; all with fibrosis) presented 17 MACE, comprising: SCD events (n=7, 41.2%; including three patients with an ICD, five with at least one SCD major classical risk factor and an ESC score≥5% and two with no risk factors and an ESC score<4%); atrial fibrillation/stroke (n=6, 35.3%); heart failure (n=1, 5.9%); syncope (n=3, 17.6%). An ICD was implanted in 11 patients (four for secondary prevention), but in only 61.5% of patients with a score≥6%. Only obstruction significantly increased MACE risk (odds ratio 3.96; P=0.035), with a non-significant trend towards a lower risk in men (OR 0.29; P=0.065). CONCLUSIONS: In young adults with HCM, MACE are common in the short term, especially in obstructive HCM and women, mostly arrhythmic in origin. Prophylactic ICD implantation is frequent and does not strictly follow the guidelines, while the use of European/USA guidelines is helpful but imperfect in identifying SCD risk.