Electrophysiological effects of disopyramide and quinidine on guinea pig atria and canine cardiac purkinje fibers. Dependence on underlying cholinergic tone.

• DOI: 10.1161/01.res.46.5.660
• Publication Date: 2012-06-12T00:17:09Z
• Authors: M J Mirro; A M Watanabe; J C Bailey
• Keywords: Quinidine; Purkinje fibers; Disopyramide

We studied the role of anticholinergic properties disopyramide and quinidine in mediating electrophysiological effects these agents on isolated cardiac tissue.In right atria, disopyramide, quinidine, procainamide administered alone elicited negative chronotropic responses.However, after cholinergic stimulation with physostigmine (1 X 10" 6 M), produced a positive response.Procainamide, when under same conditions increased stimulation, responses similar to those observed it was given alone.In Purkinje fibers, superfused for 5 minutes significantly prolonged action potential duration (APD).When fibers pretreated isoproterenol x 10"' M) plus acetylcholine (3 10~7 shortened APD.Atropine also APD exposed both acetylcholine.In experiments, consistently APD, blunted isoproterenol.Thus, alone, prolong but setting adrenergic-cholinergic they shorten APD.Procainamide, acetylcholine, prolongs as is alone.These data demonstrate that exert important electrophysiologic atria ventricular conducting systems.These may contribute antiarrhythmic arrhythmogenic compounds.