Optimal positioning of temporary epicardial atrial pacing leads after cardiac surgery

OBJECTIVES: Atrial pacing plays an important role in preventing low output syndrome and arrhythmia after cardiac surgery. We studied the optimal positioning for temporary epicardiac atrial pacing. METHODS: The performance of temporary epicardiac atrial pacing leads was examined after 13 cases of elective coronary artery bypass grafting between October 1999 and January 2000. Two bipolar electrode leads were used--1 on the cephalic atrial wall between the left and right atrial appendages, where the Bachmann bundle indwells (site A), and the other on the interatrial groove (site B). To assess pacing performance on postoperative days 1, 2, and 7, we measured 3 pacing patterns--bipolar use of sites A and B leads, and combined use of the 2 with the site A lead acting as the negative electrode and the site B lead as the ground. The pacing threshold was measured at a 0.5 ms pulse width, using the P wave amplitude and slew rate as indicators of sensing performance. RESULTS: Bipolar pacing both at sites A and A-B was superior to that at site B in pacing threshold and sensing parameters. CONCLUSIONS: The negative electrode at site A is mandatory for high atrial pacing and sensing performance.