Electrophysiologic properties of prenalterol.
We assessed the electrophysiological properties of prenalterol, a new beta-selective agonist, in 10 patients with normal and 10 patients with delayed atrioventricular (A-V) conduction times. We evaluated sinus node function, A-V conduction times, refractory periods, atrial or ventricular arrhythmias, spontaneous or induced by the single extrastimulus technique during basal conditions, 5 minutes after a first dose of 20 micrograms/kg of prenalterol, and 5, 15 and 30 minutes after a second injection of the same dose. Prenalterol increased heart rate about 20%, with statistically significant shortening of right atrial refractory periods, A-V nodal functional and effective refractory periods and A-H interval in both groups after the first dose. In the 6 patients with sick sinus syndrome, prenalterol increased heart rate significantly and decreased maximum sinus node recovery time which reached a statistically significant value (P less than 0.05) 5 and 30 minutes after the second dose. At the highest dose, prenalterol seemed to increase the number of ventricular and/or atrial arrhythmias only in those patients with the arrhythmias before treatment. Prenalterol increases heart rate and decreases A-V node conduction times. The shortening of maximum sinus node recovery time in patients with the sick sinus syndrome, especially if confirmed after oral administration, could indicate a specific use of this drug in patients with sinus bradycardia or atrial fibrillation with a slow ventricular response.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D001145:Arrhythmias, Cardiac / Q000139:chemically induced; D001283:Atrioventricular Node / Q000187:drug effects; D004594:Electrophysiology; D006329:Heart Conduction System / Q000187:drug effects*; D006801:Humans; D011217:Practolol / Q000031:analogs & derivatives* / Q000494:pharmacology; D011294:Prenalterol; D011690:Purkinje Fibers / Q000187:drug effects; D012804:Sick Sinus Syndrome / Q000188:drug therapy; D012849:Sinoatrial Node / Q000187:drug effects
D000318:Adrenergic beta-Agonists; D011294:Prenalterol; D011217:Practolol