Effects of drive train stimulus intensity on ventricular refractoriness in humans.

Abstract

Increasing S1 intensity results in clinically significant, progressive shortening of VERP in man. This effect is independent of S2 intensity. The prolonged time course of the change in VERP after an increase in S1 intensity and the attenuation of this effect by autonomic blockade are consistent with stimulation of sympathetic nerve terminals and catecholamine release as a result of intense stimulation.