Clinical experience with intravenous metoprolol in supraventricular tachyarrhythmias. A multicentre study.

The efficacy of metoprolol, 5-15 mg i.v., in the treatment of supraventricular tachyarrhythmias was evaluated in a multi-centre study involving 142 patients, 28 of whom had paroxysmal atrial tachycardia, 35 atrial flutter and 79 atrial fibrillation. A good control of heart rate (reduction of greater than or equal to 25% or to less than 100 beats/min) was obtained in 68% of the patients and a further 18% showed a reduction in heart rate of at least 10% or to less than or equal to 150 beats/min. Conversion to sinus rhythm occurred in 57% of the patients with paroxysmal atrial tachycardia. As would be expected, the conversion rate was lower in patients with atrial flutter or fibrillation (23% and 13%, respectively). The drug was well tolerated, and marked hypotension or hypotensive symptoms occurred mainly in patients with initial hypotension or congestive heart failure. The effects observed in this study are in agreement with previous reports for other beta-blocking agents.