The antifibrillatory potency of aprindine, mexiletine, tocainide and lignocaine compared on Langendorff-perfused hearts of rabbits and guinea-pigs.
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.
D000813:Anilides / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D001073:Aprindine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000502:physiology; D066298:In Vitro Techniques; D007192:Indenes / Q000494:pharmacology*; D008012:Lidocaine / Q000494:pharmacology*; D008297:Male; D008801:Mexiletine / Q000494:pharmacology*; D010042:Ouabain / Q000037:antagonists & inhibitors; D010477:Perfusion; D011437:Propylamines / Q000494:pharmacology*; D011817:Rabbits; D016677:Tocainide; D014693:Ventricular Fibrillation / Q000188:drug therapy*
D000813:Anilides; D000889:Anti-Arrhythmia Agents; D007192:Indenes; D011437:Propylamines; D008801:Mexiletine; D016677:Tocainide; D010042:Ouabain; D001073:Aprindine; D008012:Lidocaine