Circadian patterns in the occurrence of malignant ventricular tachyarrhythmias triggering defibrillator interventions in patients with hypertrophic cardiomyopathy.

Background: Sudden death in hypertrophic cardiomyopathy (HCM) has been reported to occur most frequently in the early morning hours, similar to the pattern observed in ischemic heart disease. However, little is known about the circadian pattern of life-threatening arrhythmias in HCM in the contemporary era of the implantable cardioverter-defibrillator (ICD).

Objective: The purpose of this study was to determine the time of day when appropriate device interventions occur for ventricular tachycardia (VT)/ventricular fibrillation (VF) in HCM patients.

Implantable cardioverter-defibrillators and prevention of sudden cardiac death in hypertrophic cardiomyopathy.

Context: Recently, the implantable cardioverter-defibrillator (ICD) has been promoted for prevention of sudden death in hypertrophic cardiomyopathy (HCM). However, the effectiveness and appropriate selection of patients for this therapy is incompletely resolved.

Objective: To study the relationship between clinical risk profile and incidence and efficacy of ICD intervention in HCM.