Changes in ventricular fibrillation threshold induced by contrast agents during acute coronary artery occlusion

In the first few hours after acute coronary thrombosis, clinical coronary angiography is associated with enhanced risk of ventricular fibrillation. In these experiments, the ventricular fibrillation threshold (VFT) was measured in anesthetized dogs before and during acute occlusion of the left circumflex coronary artery. Ischemia alone reduced the fibrillation threshold. Angiography with 1- or 2-ml does of Renografin 76 lowered VFT significantly more than did equal doses of iohexol or iopamidol. It is concluded that nonionic agents may be safer for coronary angiography in the presence of acute coronary insufficiency.