Coronary artery perforation is a rare and serious complication in coronary angioplasty. Some patients complicated by coronary perforation may develop cardiac tamponade, which is generally due to massive hemorrhage in the pericardial space between the epicardium and the pericardium. We report a case of coronary artery perforation producing impending tamponade, which was successfully treated by transcatheter embolization of distal circumflex artery using polyvinyl alcohol.