Antiarrhythmic Action of Calcium Antagonists

Abstract

The marked coronary dilating and negative inotropic effect of prenylamine /1/ as well as that of verapamil /2/ was described in the early sixties, however Fleckenstein et al. /3/ were the first to show that these agents are capable of depressing cardiac contractility in concentrations not yet affecting the action potential. Thus they inhibit the electromechanical coupling. The authors attributed this effect to a drug induced depression of the transmembrane inward Ca²⁺ current hence the name: calcium antagonists /Ca-s/. Later Grün and Fleckenstein /4/ have shown electromechanical uncoupling effect of CA-s in the smooth muscle too. The steadily growing interest has initiated a number of experimental and clinical studies showing that in addition to its scientific importance introduction of this new group of drugs into clinical therapy represents a major breakthrough.