Cardiac electrophysiologic effects of adaprolol maleate, a new beta-blocker, in closed chest dogs.
Adaprolol maleate (adaprolol) is a new beta-adrenergic receptor blocker. The cardiac electrophysiologic characteristics and the duration of action of adaprolol were studied in intact anesthetized dogs. The electrophysiologic parameters were evaluated before drug administration and 10 min after the administration of maintenance infusion of adaprolol (N = 5). The duration of action was measured during constant infusion of isoproterenol, giving the adaprolol as a single i.v. bolus in different concentrations (N = 5). Results of this study showed that adaprolol has marked electrophysiologic effects. Its major action was on sinus node; it prolonged the basic sinus cycle length and had significant effect on intrinsic automaticity as reflected by the prolonged corrected sinus node recovery time and sinuatrial conduction time. There was, also, direct effect on atrial function and AV nodal function. Adaprolol prolonged the effective refractory period of the His-Purkinje system and the ventricle. The onset of action was very rapid (within seconds) and the duration of action was relatively prolonged (3 hrs). The potency of adaprolol's electrophysiologic effects are higher compared to other widely used beta-blockers. Adaprolol appears to be a potent beta-blocker with particularly strong antiarrhythmic effect and it would be very useful in the treatment of both supraventricular and ventricular tachyarrhythmias and ectopic beats.
Polgar
P
P
Center for Drug Design and Delivery, College of Pharmacy, University of Florida, Gainesville 32610.
Bodor
N
N
D000218:Adamantane / Q000031:analogs & derivatives* / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D004285:Dogs; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D006334:Heart Function Tests; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D010648:Phenylacetates / Q000494:pharmacology*
D000319:Adrenergic beta-Antagonists; D010648:Phenylacetates; D007545:Isoproterenol; D000218:Adamantane; C068416:adaprolol