Identifying patients at risk for sudden death and preventing sudden death in HCM is difficult. We studied cardiac events during follow-up of 13 patients with HCM who received an ICD because of aborted sudden death (10 people) or sustained ventricular tachycardia (3 people). Findings were compared to 215 patients with an ICD and other structural heart disease or ventricular fibrillation but no HCM.
	After an average follow-up of 2 years, 2 of 13 patients in group 1 received "appropriate" shocks. The accumulated rate of shocks was 21% in HCM patients and 66% in non-HCM patients after 3 1/2 years. We saw little repeat ventricular tachycardia/fibrillation during follow-up in HCM patients. No deaths occurred.
	This study suggests that ventricular tachyarrhythmias may not always be the primary reason for fainting and sudden death in HCM patients. The ICD seems to have less impact on prognosis in patients with HCM than in patients with other causes of aborted sudden death.

Title: Hypertrophic cardiomyopathy: role of the implantable cardioverter-defibrillator
Authors: Primo J, Geelen P, Brugada J, Filho AL, Mont L, Wellens F, Valentino M, Brugada P Cardiovascular Center, Onze Lieve Vrouw Hospital, Aalst, Belgium. 
PMID: 9562010, UI: 98220477 
Comment in: J Am Coll Cardiol 1998 Apr;31(5):1086-8