Intravenous Diltiazem for Treatment of Supraventricular Tachycardia after Coronary Artery Bypass Surgery

Between 1995 and 1997, 180 patients who had undergone coronary artery bypass grafting were given intravenous diltiazem for conversion of supraventricular tachycardia to sinus rhythm or control of ventricular rhythm in atrial fibrillation. The patients were divided into three groups of 60 each: group 1 required no inotropic support; group 2 had mild inotropic support with dopamine; group 3 had high-dose inotropic support with adrenalin and dopamine. Thirty-eight patients in group 1 (63%), 40 in group 2 (67%), and 32 in group 3 (53%) responded to one or two doses of diltiazem. There was no difference between the groups in terms of the success rate of the treatment (p > 0.05). Additional procedures were needed in 70 patients including cardioversion in 20 (12 in group 1, 8 in group 2). Mean cardiac index was significantly increased and mean pulmonary artery pressure was significantly decreased in all three groups after diltiazem treatment. After the first dose of diltiazem (0.25 mg·kg −1 ), the mean heart rate decreased from 141.5mg·kg −1 ± 3.8, 136.9 ± 8.5, and 140.2 ± 4.7 to 118.2 ± 5.1, 101.2 ± 6.7, and 105.6 ± 16.8 in groups 1, 2, and 3, respectively. The maximum decrease was seen after 5 minutes. After the second dose of diltiazem (0.35 mg·kg −1 ), although mean heart rates were not significantly decreased, 45% of group 1, 44% of group 2, and 46% of group 3 patients who did not respond to the first dose of diltiazem, converted to sinus rhythm. In the early postoperative period after coronary artery bypass graft surgery, diltiazem was of benefit in the treatment of supraventricular tachycardia and atrial fibrillation or flutter. This treatment may be especially useful in patients who are in poor hemodynamic condition.