Metrizoic acid (Isopaque coronar) used in man for cardiac angiography

Isopaque Coronar, a radiopaque agent, was given (10,000 injections) to 2,028 patients during angiocardiographic studies done over a three-year period. With two exceptions, all complications occurred during right coronary artery injection. Seven cases of ventricular fibrilation, and 5 of marked bradycardia/asystole, were associated with injection of the medium. Isopaque Coronar is well tolerated by patients during cardiac examinations. Factors which may help to explain the low complication rate are discussed.