Ineffective ICD therapy due to excessive alcohol and exercise.

A 49-year-old man with dilated cardiomyopathy and an ICD received eight unsuccessful shocks for a single episode of ventricular tachycardia after excessive alcohol intake and exercise. The patient had low defibrillation thresholds just 8 days prior to his event during a routine 6-week postimplant electrophysiological study. Defibrillation threshold testing after his incident confirmed the low energy requirement for ventricular tachycardia termination. A previous animal study reported that intravenous ethanol elevates the defibrillation energy in a dose dependent manner. However, a recent study in humans showed that modest alcohol intake had no effect on defibrillator thresholds. This case report supports the animal data and suggests that excessive alcohol consumption can cause a life-threatening situation in ICD patients.