Ventricular arrhythmias, sudden death, and prevention in patients with hypertrophic cardiomyopathy.

Sudden unexpected death, often occurring in young asymptomatic patients, is the most devastating facet of the natural history of hypertrophic cardiomyopathy (HCM). It appears to be the consequence of primary ventricular tachyarrhythmias arising in an electrically unstable myocardial substrate characterized by disorganized cellular architecture, ischemia, cell death, and replacement scarring. Although identification of the HCM patient subset at high risk for a catastrophic event with precision continues to present challenges, treatment strategies for the prevention of sudden death are now available. In particular, the implantable cardioverter-defibrillator has a high degree of efficacy in sensing and terminating potentially lethal ventricular tachyarrhythmias and a life-saving role in both the primary and secondary prevention of sudden cardiac death in HCM.