title: Clinical electrophysiological properties of penbutolol: a non-selective beta-blocking agent.
abstract: The electrophysiological effects of the beta-adrenergic blocking agent penbutolol (4 mg i.v.) were studied in 15 patients by means of intracardiac recording using the extra-stimulus technique and rapid atrial pacing. The following effects were observed. (1) Significant prolongation of the sinus cycle length (16%). (2) Significant prolongation of the AV-nodal conduction time during sinus rhythm (12%). (3) Significant prolongation of the AV-nodal conduction time with increasing atrial pacing rate (16--29%). At 150/min, 4 of 7 patients with intact AV-conduction under baseline conditions developed second degree AV-block 15 to 30 min after penbutolol administration. (4) Significant prolongation of the effective refractory period of the AV-node (19%). Penbutolol had no effect on the intraventricular conduction, on intraatrial conduction or on the corrected sinus node recovery time.
mesh_terms: D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D001283:Atrioventricular Node / Q000187:drug effects*; D002304:Cardiac Pacing, Artificial / Q000379:methods; D004594:Electrophysiology; D005260:Female; D006321:Heart / Q000187:drug effects*; D006327:Heart Block / Q000139:chemically induced; D006329:Heart Conduction System / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D010394:Penbutolol / Q000009:adverse effects / Q000494:pharmacology*; D011412:Propanolamines / Q000494:pharmacology*
chemical_list: D011412:Propanolamines; D010394:Penbutolol