[Study of electrophysiological effects of betaxolol].

Betaxolol is a new cardioselective beta-blocker without any intrinsic sympathomimetic activity. A study of the cardiac electrophysiological effects of this molecule used intravenously was carried out in 20 patients. Betaxolol prolongs the sinus cycle (+ 25%, p 0.001), prolongs the sino-atrial conduction time (+ 20.1%) and atrio-hissian conduction time (+ 10.8%, p 0.001), and prolongs the refractory periods at all levels: atrial (+ 8%), nodal (+ 20.8%), right ventricular (+ 4.3%). These findings confirm the electrophysiological characteristic effects of the beta-blockers series; however, the moderate but significant increase of the refractory ventricular period, seems to provide this molecule with a certain degree of originality in this therapeutic class.