[Prevention of effort-induced ventricular arrhythmia using verapamil].

In this study prophylactic antiarrhythmic effects of verapamil on exercise-induced ventricular arrhythmias were evaluated in a total of 22 patients. All patients displayed frequent and/or complex ventricular arrhythmias during repeated exercise tests under control conditions. After two control exercise tests, all patients were treated with 120 mg verapamil given every 8 h orally for 4 days. On the 3rd and 4th day of treatment the exercise tests were repeated. The results were that verapamil caused a significant reduction in the incidence and severity of exercise-induced ventricular arrhythmias in 13 out of 22 patients. In patients with concomitant significant ST-segment depression, a prophylactic action could be demonstrated in nine out of ten cases. The antiarrhythmic effect was independent of changes in heart rate. In patients with myocardial ischaemia, a reduction in myocardial oxygen consumption and direct electrophysiological effects (suppression of the "slow response" and/or an increase in the resting potential of the "depressed fast response") can be discussed as mechanisms of action. Also, a suppression of "triggered activity" or a direct inhibition of adrenergic effects must be considered. According to our results and the literature, calcium antagonists (verapamil type) proved to be suitable drugs for the treatment of exercise-induced ventricular arrhythmias, particularly in patients with concomitant myocardial ischaemia.