Prevention of contrast-induced bradycardia during coronary angiography.

A double-blind study of 90 patients undergoing coronary angiography was performed to determine the safety and efficacy of 0.6 mg atropine sulfate in preventing contrast-induced bradycardia. Coronary angiography performed using the Sones technique resulted in ventricular pauses of greater than 2 seconds in 3 of 49 patients (6%) who received prophylactic atropine and 20 of 41 patients (49%) receiving placebo. Though the pauses were usually due to atrial asystole, 26% of those with greater than 2 second pauses did so because of transient complete heart block. Prophylactic atropine did increase resting heart rate but did not cause other arrhythmias or increase the frequency of angina pectoris despite the presence of severe coronary disease. Our data indicate that contrast-induced asystole is very common, cannot be predicted by consideration of "precatheterization data," and can be prevented effectively and safely by use of prophylactic atropine sulfate.