The Effect of Caffeine on Ventricular Ectopic Activity in Patients With Malignant Ventricular Arrhythmia

n=50 consecutive patients with malignant ventricular arrhythmia (recurrent ventricular tachycardia [42%], ventricular fibrillation [6%], or symptomatic nonsustained ventricular tachycardia [52%]), mean age 61 years, 84% with ischemic heart disease or cardiomyopathy.

200 mg of caffeine mixed with decaffeinated coffee

Decaffeinated drink alone (administered on successive days in a crossover design)

Ventricular ectopic activity (total or repetitive ventricular arrhythmia) measured via continuous electrocardiographic recordings during a 30-minute control period, 3-hour observation period, and hourly bicycle exercise testssurrogate