Acute occlusion of left internal mammary artery graft during dual-chamber pacemaker implantation.

A patient who had undergone bypass surgery 5 yr earlier, including left internal mammary artery (LIMA) grafting to the left anterior descending artery, underwent transvenous dual-chamber permanent pacemaker implantation for persistent advanced atrioventricular block. Intraoperative LIMA graft obstruction occurred, resulting in anterior myocardial infarction that was treated successfully by primary percutaneous transluminal coronary angioplasty and stenting. This is the first report of the occurrence of this complication during pacemaker implantation.