A 73 year-old male patient with multi-vessel coronary artery disease underwent coronary artery bypass grafting (CABG) based on worsening chest pain lasted for 3 months.His condition was good during the first week post operation.However, on the 7th day after the surgery, the patient suddenly had low pressure and lost his consciousness while the pulse was not found and cyanosis was shown on both the face and lips.Echocardiography clearly pointed out that left ventricle was constricted by delayed pericardial tamponade.After an emergency surgery, fresh blood clots were cleared out in the inferior lateral side of pericardium and therefore the constriction had been resolved.