The authors report a case of percutaneous transluminal coronary angioplasty of the circumflex artery complicated by occlusion of the non-diseased left anterior descending artery by spasm. During advanced cardiac life support, required for the subsequent cardiac arrest, intra-coronary nitrates and calcium antagonists were administered. After 45 minutes, the spasm resolved, but N probably as a result of prolonged blood stasis N a thrombus appeared in the left main artery. While attempting to stent the left main, the thrombus was mechanically dislodged, leaving the epicardial coronary tree free, with a good flow.