Key points are not available for this paper at this time.
The effectiveness of three new antiarrhythmic drugs, aprindine, mexiletine and tocainide in elevating ventricular fibrillation threshold measured in the Langendorff-perfused rabbit heart and in protecting against ouabain-induced arrhythmias in the Langendorff-perfused guinea-pig heart has been compared with that of lignocaine. All these drugs have produced a significant rise in the threshold but quantitatively mexiletine was about equal to, tocainide five times less and aprindine thirty-eight times more potent than lignocaine in this effect. Aprindine differed from the other three drugs in that it had a slow onset of action and its effect was not entirely removed upon reperfusion with the drug-free solution. Only aprindine and mexiletine provided complete protection against ouabain-induced ventricular fibrillation while 3 of 6 and 4 of 6 hearts fibrillated in the presence of lignocaine or tocainide respectively.
Almotrefi et al. (Mon,) studied this question.