Treatment of arrhythmias with pindolol

Pindolol, a beta adrenergic blocking agent, was given intravenously to 30 patients with cardiac arrhythmias. A rapid ventricular rate was slowed in 7 patients with atrial fibrillation, with later spontaneous conversion to sinus rhythm in 2 patients. A rapid ventricular rate was slowed in 6 of 7 patients with atrial flutter. In 3 of these 7 patients, the rhythm converted to atrial fibrillation. In 2 of these 3 patients, the rhythm later converted to sinus rhythm, probably due to drug in one patient. One patient with atrial tachycardia became hypotensive after a second dose of pindolol. Atrioventricular junctional tachycardia was converted to sinus rhythm in 2 patients, one with digitalis toxicity. Sinus tachycardia was converted to sinus rhythm in 3 patients. Paroxysmal repetitive ventricular tachycardia due to digitalis toxicity was abolished in one patient. Pindolol abolished or greatly mduced frequent premature ventricular beats in 10 patients, 6 with definite or possible digitalis toxicity. Pindolol had no effect on frequent ventricular premature beats in 4 patients, none receiving digitalis. Pindolol abolished frequent atrial premature beats in 3 patients, one with definite and one with possible digitalis toxicity. The pindolol was useful in the treatment of cardiac arrhythmias in 24 of these 30 patients.