title: Implantable defibrillators and prevention of sudden death in hypertrophic cardiomyopathy.
abstract: Hypertrophic cardiomyopathy (HCM) is the most common cause of sudden cardiac death in young people, including trained athletes. The implantable cardioverter-defibrillator (ICD), although initially designed as a treatment for older patients with coronary artery disease, has more recently proved to be a safe and effective therapeutic intervention in young patients with HCM, both for primary or secondary prevention of sudden death. The largest such report of >500 patients showed that the ICD intervened appropriately to abort ventricular tachycardia/fibrillation (VT/VF) in 20% of patients over an average follow-up period of only 3.7 years, at a rate of about 4% per year in those patients implanted prophylactically, and often with considerable delays of up to 10 years. Extensive experience with high-risk HCM patients showed that appropriate device discharges for VT/VF occur with similar frequency in patients with 1, 2, or > or = 3 noninvasive risk markers. Despite the extreme morphology characteristic of HCM, often with massive degrees of left ventricular (LV) hypertrophy and/or LV outflow tract obstruction, ICDs performed in a highly effective fashion, with failure to convert life-threatening arrhythmias extraordinarily rare. In conclusion, in a large high-risk HCM cohort, ICD interventions for life-threatening ventricular tachyarrhythmias were frequent and highly effective in restoring normal rhythm. An important proportion of ICD discharges occurred in primary prevention patients with only one risk factor. Therefore, a single marker of high risk may represent sufficient evidence to justify the recommendation for a prophylactic ICD in selected patients with HCM.
authors.affiliation: Hypertrophic Cardiomyopathy Center, Minneapolis Heart Institute Foundation, Minneapolis, Minnesota 55407, USA. hcm.maron@mhif.org
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Maron
authors.forename: Paolo
authors.initials: P
authors.lastname: Spirito
mesh_terms: D002312:Cardiomyopathy, Hypertrophic / Q000453:epidemiology* / Q000517:prevention & control*; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data*; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D016896:Treatment Outcome