Although intraoperative coronary angioplasty has the potential to enhance revascularization in selected patients undergoing coronary bypass, this technique is only rarely performed, due in part to the lack of angiographic monitoring. Accordingly, to develop angiographic techniques potentially applicable to intraoperative angioplasty, 6 conditioned dogs were placed on full cardiopulmonary bypass, the aorta was cross-clamped, and the heart arrested with cold cardioplegia solution. After 45 minutes of arrest, selective coronary angiography was performed employing catheters introduced through a proximal aortotomy. Small-volume contrast injections resulted in excellent opacification; however, the contrast agent stagnated within the coronary tree. Fortunately, intracoronary flush injection of the saline-cardioplegia solution resulted in immediate and complete contrast washout. After discontinuation of bypass, echocardiography revealed normal left and right ventricular function. Histopathologic analysis of tissue specimens from animals in which contrast was flushed documented the presence of normal coronary arteries and myocardium. These findings demonstrate methods by which intraoperative coronary angiography can be performed in the arrested heart without having adverse effects on either the cardiac function or histologic appearance. These techniques may have application for the performance of intraoperative angioplasty.