May 1, 1981

Cardiac electrophysiologic effects of quinidine and propranolol isomers in anesthetized dogs: concentration-response relationships

Journal of Cardiovascular Pharmacology
P JaillonG Cheymol


Electrophysiological properties of quinidine and the two isomers of propranolol were compared in pentobarbital-anesthetized dogs using His bundle recordings and programmed stimulation in order to differentiate the effects resulting from beta-blockade from those related to nonspecific membrane-stabilizing effects. Quinidine in the plasma concentration range of 2.7-20 microM/liter resulted in concentration-dependent increases in atrionodal and His-Purkinje system conduction times and in the atrial effective refractory period. Quinidine did not produce any significant concentration-dependent change in atrioventricular (AV) nodal and ventricular refractory periods, sinus node automaticity, or QTc interval duration. Propranolol isomers in concentration range of 0.03-0.85 microM/liter produced a concentration-dependent increase in atrionodal conduction time but exerted no significant effect on His-Purkinje conduction time, QTc duration, or ventricular refractory period. Both isomers increased the atrial effective refractory period, but with slopes of concentration-response regression lines which were significantly different from those of quinidine. Only l-propranolol produced concentration-dependent increases in AV nodal refractory p...Continue Reading

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Mentioned in this Paper

Sinoatrial Node
Molecular Stereochemistry
Refractory Period, Electrophysiological
Anesthesia Procedures
Refractory Period
Quinidine Measurement
Cardiac Conduction System
Structure of Atrioventricular Node

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