A patient with previous coronary artery bypass grafting developed an iatrogenic pneumothorax, along with pneumopericardium and pneumomediastinum, after elective implantation of a cardiac resynchronization therapy pacemaker. There was no evidence of lead perforation, and the patient remained well and was successfully managed conservatively. We hypothesize that air tracked from the pneumothorax via microscopic pleuropericardial fistulae. ().