Verapamil infusions in the treatment of atrial tachyarrhythmias.

Ten patients with symptomatic atrial tachyarrhythmias were treated with an iv verapamil bolus (mean 8.5 mg) followed by a continuous verapamil infusion (mean dose 9.4 mg/h). The infusions were titrated to ventricular rate and continued for an average of 20 h, until oral therapy could be instituted. All patients had a significant, sustained reduction in ventricular rate during the infusion, without a significant reduction in mean arterial pressure. Although one patient complained of dizziness after 8 h of infusion therapy, the regimen was generally well tolerated and no patient had clinical worsening of heart failure. These preliminary data suggest that continuous verapamil infusions can safely and effectively control ventricular rate in patients with rapid atrial tachyarrhythmias, until oral medications can be started.