Pacing of Bachmann's Bundle After Coronary Artery Bypass Grafting

Abstract

The purpose of this randomized, prospective trial was to determine if Bachmann's bundle pacing reduces the incidence of AF after CABG. The study included 161 patients with no history of AF who were randomized to three groups. Group 1 included 50 patients as controls. Group 2 included 60 patients who had an epicardial wire placed at the lateral wall of the right atrium. In the 51 patients of group 3, the wire was placed at the Bachmann's bundle. In groups 2 and 3, atrial pacing (AAI 96 beats/min) was initiated immediately after CABG and continued for 5 days. The study endpoint was AF lasting > or = 1 minute. Baseline clinical parameters were similar in all three groups. The incidence of AF was not reduced by pacing (group 1: 42%; group 2:48%; group 3:37%; P = NS). The paced P wave duration was increased in group 2 (129 +/- 14 ms vs group 3: 96 +/- 21 ms; P < 0.05). Paced P wave duration was a risk factor for postoperative AF (odds ratio 1.015; 95% CI 1.0021-1.028; P < 0.05). Analysis comparing the pacing groups revealed a reduction in AF during Bachmann's bundle pacing (50 vs 29%; P < 0.01). Pacing thresholds were significantly better at Bachmann's bundle compared to group 2. In conclusion, an anatomically guided pacing at the Bachmann's bundle does not reduce the overall incidence of postoperative AF compared to controls. However, the Bachmann's bundle offers favorable capabilities for postoperative a trial pacing, and thus it is a preferable site for electrode placement if postoperative atrial pacing is required.

Spontaneous termination of ventricular fibrillation

“…The percentage reduction in mean P wave duration was similar in the three pacing groups but BAP resulted in a significantly greater reduction in mean P wave dispersion. By contrast, however, RAP prolonged P wave duration in the studies of Blommaert et al 19 and Goette et al 26 and prolongation of P wave duration during RAP was an independent predictor for postoperative AF in the latter study. 26 Atrial pacing may be expected to reduce bradycardia related AF.…”

“…16 23 15 25 One study compared control with RAP and pacing at Bachmann's bundle. 26 One study did not state the site of pacing, which was assumed to be RAP. 18 Pacing protocols were AAT mode, 16 21 22 24 AAI mode at 96 pulses/min, 26 AAI mode at 100 pulses/min, 17 AAI mode set at 10-20 beats above the intrinsic atrial rate, 14 15 20 25 DDD mode at a lower rate of 100 pulses/min, 23 and atrial overdrive algorithms that paced the atrium consistently above the intrinsic atrial rate.…”

“…Levy et al 22 reported lead failure in 20% of their BAP patients, evenly split between left and right atrial wires. In the study of Goette et al, 26 atrial pacing was terminated early in 6 (10%) of 60 patients in the RAP group and in 3 (5.9%) of 51 patients in the Bachmann's bundle pacing group. Pacing thresholds were significantly higher in the RAP group than in the Bachmann's bundle group (p , 0.05), but there was no difference in atrial sensing.…”

“…By contrast, however, RAP prolonged P wave duration in the studies of Blommaert et al 19 and Goette et al 26 and prolongation of P wave duration during RAP was an independent predictor for postoperative AF in the latter study. 26 Atrial pacing may be expected to reduce bradycardia related AF. The presence of atrial extrasystoles preoperatively independently predicts the development of post-CABG AF.…”

Nonpharmacologic Treatment of Postoperative Atrial Fibrillation

“…Because both atrial sensing and capture thresholds are frequently unreliable when epicardial atrial temporary pacing wires are placed routinely (lateral right atrial wall), a study placing the atrial epicardial leads at the roof of the atria, into Bachmann's Bundles (a thick, muscular strand electrically connecting the right and left atria) was performed [45]. Sixty-three patients undergoing CABG were randomized to have atrial temporary pacing wires placed at the lateral wall (37 patients) or placed at Bachmann's Bundle (26 patients).…”