[Antagonists of calcium movements and rhythm disorders]

Since transmembrane myocardiac calcium-exchanges play an important role in myocyte electrogenesis as well as in triggering and maintenance of some cardiac arrhythmias, it might be true that calcium antagonists possess antiarrhythmic properties. However, use of calcium antagonists as antiarrhythmic agents is only possible if the drug is devoid of sympathetic reflex stimulation and possesses use-dependence properties. These drugs are of most efficiency in cardiac arrhythmias (especially of supraventricular origin), caused by reentry phenomena in which part of the circuit is governed by calcicosodic cells. The use of calcium antagonists for ventricular arrhythmias is limited to some specific indications (idiopathic ventricular tachycardia with right bundle branch block and left axis, reperfusion arrhythmias...). Choice of the type and the route of administration of calcium antagonists has to take into account their pharmacokinetic specificities which can alter their antiarrhythmic potency.