Figure 61

Stored Ventricular Electrogram from an Asymptomatic 35-Year-Old Man Who Received a Defibrillator Prophylactically Because of a Family History of Sudden Death Related to Hypertrophic Cardiomyopathy and Marked Ventricular Septal Thickness (31mm).
The electrogram was obtained four years eight months after implantation of the defibrillator. The data were recorded at 1:20 a.m. while the patient was asleep. A continuous recording, at 25mm per second, is shown in four panels, with the tracing recorded from left to right in each. After four beats of sinus rhythm, ventricular tachycardia begins abruptly, at a rate of 200 beats per minute (Panel A). The defibrillator senses ventricular tachycardia and charges (Panel B). Ventricular tachycardia deteriorates into ventricular fibrillation (Panel C). The defibrillator discharges appropriately (a 20-J shock denoted by the bar, Panel D) during ventricular fibrillation and restores sinus rhythm. Adapted from Maron et al.

Maron, B.J., M.D., and others, Efficacy of Implantable Caridoverter-Defibrillators For The Prevention of Sudden Death in Patients with Hypertrophic Cardiomyopathy, The New England Journal of Medicine, Feb 10, 2000, p 365-373.

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