The electrophysiological effects of intravenous xamoterol in man.

The electrophysiological effects of xamoterol were studied in ten patients with suspected coronary artery disease by intracardiac electrography. Sino-atrial and atrioventricular conduction times were both slightly shortened by 0.1 mg/kg of xamoterol. The atrioventricular nodal refractory periods were shortened without consistent change in atrial refractoriness. This dose raised mean blood pressure by only 3 mmHg and resting heart rate by only 4 beats/min. The effects suggest a beta 1 agonist activity closer to that of prenalterol than that of pindolol under conditions of rest.