Perforation of a cardiac chamber is an infrequent but serious sequela of pacemaker lead implantation. An even rarer event is the perforation of the aorta by a protruding right atrial wire. We present here the first case in the medical literature of aortic perforation as a sequela to the implantation of a cardiac resynchronization therapy defibrillator. The patient was a 54-year-old man with idiopathic dilated cardiomyopathy who underwent the implantation of a defibrillator, with no apparent sequelae. Six hours after the procedure, he experienced cardiac tamponade and required urgent open-chest surgery. The pericardial effusion was found to be caused by mechanical friction of a protruding right atrial wire on the aortic root. The aortic root and the atrial wall were both repaired with Prolene suture, which achieved complete control of the bleeding. There was no need to reposition the atrial wire. The patient had a good postoperative recovery.