A placebo-controlled trial of continuous intravenous diltiazem infusion for 24-hour heart rate control during atrial fibrillation and atrial flutter: A multicenter study

The safety and efficacy of a 10- to 15-mg/h continuous infusion of intravenous diltiazem were evaluated in 47 patients with atrial fibrillation or flutter who first responded to 20 mg or 20 mg followed by one or more 25-mg bolus doses of open label intravenous diltiazem. Of the 47 patients, 44 responded to the bolus injection and were randomized under double-blind conditions to receive either a continuous infusion of intravenous diltiazem (10 to 15 mg/h) (23 patients) or placebo (21 patients) for up to 24 h.Seventeen (74%) of the 23 patients receiving diltiazem infusion and none of the 21 with placebo infusion maintained a therapeutic response for 24 h (p < 0.001). Over 24 h, patients receiving diltiazem infusion lost response significantly more slowly than did those receiving placebo infusion (p < 0.001). Nonresponders to the double-blind infusion were given an additional bolus injection of open label intravenous diltiazem and administered an open label 24-h intravenous diltiazem infusion. The overall proportion of patients maintaining a response to a 24-h infusion of intravenous diltiazem under double-blind or open label conditions combined was 83% (34 of 41).Efficacy of the 24-h infusion of intravenous diltiazem was similar in elderly versus young patients, those who did versus those who did not receive digoxin and those weighing