Are ioxaglate and iopamidol equally safe and well tolerated in cardiac angiography? A randomized, double-blind clinical study

A randomized, double-blind, parallel-group study was performed in 50 patients undergoing left ventriculography and coronary arteriography to evaluate ECG changes and the effects on left ventricular function of a low-osmolar lonic contrast agent, ioxaglate, as compared with a low-osmolar nonionic contrast medium, iopamidol. Twenty-five patients received ioxaglate (group 1) and 25 patients received iopamidol (group 2). All patients underwent 48 hours of continuous ECG recording beginning 24 hours before the cardiac catheterization. Left ventricular systolic and end-diastolic pressure, peak positive dp dt, and dp/dt/P ratio were measured immediately before and after left ventriculography and 3 minutes later. Left ventricular systolic pressure did not change after injection of either contrast medium. Left ventricular and-diastolic pressure increased by 30% in group 1 (p <0.01) and by 22% in group 2 (p <0.01) immediately after left ventriculography. A further increase by 45% in group 1 (p <0.01) and by 24% in group 2 (p <0.01) was observed 3 minutes later. No differences were observed between values obtained in the two groups. Peak positive dp dt did not change immediately after injection of either contrast medium but decreased by 5% (not significant) in group 1 and by 7% (p <0.02) in group 2 three minutes after left ventriculography. There were no significant differences between the two groups. Analysis of continuous 48-hour ECGs showed that both ioxaglate and iopamidol induced a slight increase (by 8% and 7%, respectively; p <0.05) in heart rate during injection with early and complete recovery. A significant increase in the frequency of ventricular premature complexes (total number/1000/hr) was observed in group 2 during the injection period and during the first hour after completion of contrast injection with respect to the extreme intervals (p <0.05). Furthermore, bigeminal rhythm, pairs, and R-on-T ventricular premature complexes increased by 24% in group 1 and by 636% in group 2 (p <0.02) during injection. PR interval, QRS width, corrected QT interval and ST segment did not change throughout the study. Thus results of our study show that despite simillar effects of ioxaglate and iopamidol on left ventricular function, the occurrence of potentially harmful ventricular arrhythmias is more frequent with iopamidol.