Pacing to prevent atrial fibrillation after coronary artery bypass grafting. What works, what doesn't: insights from Bachmann's Bundle pacing.
Atrial fibrillation (AF) occurs in about 30% of patients after open heart surgery and is associated with longer hospital stay and greater cost. Therefore, prophylactic measures are warranted to reduce the incidence of AF in postoperative patients. In addition to pharmacologic approaches, various atrial pacing strategies (right atrial, biatrial, and Bachmann's Bundle pacing) have been evaluated. Although, meta-analyses including several studies seem to demonstrate an overall benefit of atrial pacing, many findings are conflicting. The impact of Bachmann's bundle (BB) pacing on postoperative AF was studied in a recent randomized, prospective trial that included 161 patients. The incidence of postoperative AF was not reduced by BB pacing or right atrial pacing compared to non-paced controls (37% vs. 48% vs. 42%; P = ns). An important finding of this study was, however, that the paced P-wave duration, a risk factor for postoperative AF, was increased during right atrial pacing compared to BB pacing. In addition, pacing thresholds were significantly better at BB compared to right atrial locations. Thus, in contrast to biatrial pacing strategies, pacing at BB does not reduce the overall incidence of postoperative AF. However, BB offers favorable pacing capabilities and is less arrhythmogenic compared to right atrial pacing during the postoperative period.