CENTROGENIC CARDIAC ARRHYTHMIA INDUCED BY ACONITINE: A NEW “MODEL” FOR SCREENING OF ANTI-ARRHYTHMIC DRUGS

In the search of new antiarrhythmic agents, experimental techniques for evaluation of their activity are very important. One approach can be to study the effect of newer agents on the basic properties of the cardiac muscle (refractory period, conduction velocity, excitability and automaticity). Such a study will be of more fundamental interest but will not provide a clear cut idea about the therapeutic implication of the agent. A more direct approach is to study the potential compounds against experimental cardiac arrhythmias. Accordingly various models of experimentally induced cardiac arrhythmias have been utilized for the screening of antiarrhythmic agents. Dawes (1) has critically reviewed various methods of inducing cardiac arrhythmias which has been used for evaluating the anti-arrhythmic property of newer agents. So for five types of methods viz. Levy's hydrocarbon adrenaline (2), barium chloride or aconitine induced auricular fibrillation (1, 3), electrical stimulation induced auricular or ventricular arrhythmias (4), iniury stimulation induced auricular flutter (5) and coronary ligation arrhythmia (6) have been used for screening purposes. In designing the experimental ‘models’ the investigators have tried their best to produce experimental cardiac arrhythmias which may resemble the clinical conditions. We have earlier demonstrated (7-9) that administration of aconitine (20 μg) into the lateral cerebral ventricles of dogs produces centrogenic cardiac arrhythmias in 100% cases. Hence it was thought worthwhile to assess the suitability of aconitine induced centrogenic cardiac arrhythmia “model” for the screening of potential antiarrhythmic agents.