Ineffectiveness and potential proarrhythmia of atrial pacing for atrial fibrillation prevention after coronary artery bypass grafting

Background. Atrial pacing is often used empirically to suppress atrial ectopy and prevent atrial fibrillation after coronary artery bypass grafting. Methods. To determine whether atrial overdrive pacing reduces atrial fibrillation and atrial ectopy after coronary artery bypass grafting, 100 patients were randomized to no atrial pacing (Control) Versus AAI pacing at 10 beats/min or more above the resting heart rate (Paced), started by postoperative day 1 and continued through day 4. Major end points were new atrial fibrillation and frequency of atrial ectopy during the first 4 days after coronary artery bypass grafting. Results. Atrial fibrillation occurred by day 4 in 13 of 51 (25.5%) Paced and in 14 of 49 (28.6%) Control patients, p = 0.90. Control patients who developed atrial fibrillation had significantly more atrial ectopy than those who did not. Atrial ectopy was paradoxically more frequent in the Paced group (2,106 +/- 428 versus 866 +/- 385 per 24 hours, p = 0.0001). Loss of capture, sensing, and consistent atrial pacing occurred frequently during atrial pacing. Conclusions. Contrary to prevailing opinion and practice, postoperative atrial overdrive pacing significantly increases atrial ectopy and does not reduce the likelihood of atrial fibrillation. (C) 2000 by The Society of Thoracic Surgeons.