Clinical study on the application of two-dimensional speckle tracking imaging to evaluate the atrial synchrony of Bachmann's bundle pacing in patients with sick sinus syndrome.

BACKGROUND

While pacemaker therapy is well-established for sick sinus syndrome (SSS), the comparative electrophysiological benefits of different atrial pacing sites remain unresolved. This study aimed to compare the effects of right atrial appendage pacing (RAAP) and Bachmann's bundle pacing (BBP) on atrial synchrony in patients with SSS using two-dimensional speckle tracking imaging (2D-STI).

METHODS

A prospective, randomized, single-center analysis was conducted on 72 SSS patients, randomized into RAAP (n = 35) and BBP (n = 37) groups. Electrocardiogram and 2D-STI were employed to assess postoperative pacing parameters and echocardiographic indicators, including P-wave characteristics, atrial electromechanical delay (AEMD), and ventricular function metrics. Evaluations were performed preoperatively and at 1- and 3-month follow-ups, with additional device interrogation at 1 year.

RESULTS

At 1 month post-surgery, significant differences were observed between the groups in paced P-wave duration, interatrial mechanical delay (IAMD), inter- and intra-right AEMD, and ventricular pacing percentage (P < 0.05 for all). By 3 months, these differences persisted, with the BBP group demonstrating significantly greater improvements in atrial synchrony, reflected by lower IAMD and AEMD values (P < 0.05). The BBP group also showed favorable trends in ventricular dimensions. At the 1-year follow-up, the BBP group had a significantly lower atrial arrhythmia burden compared to the RAAP group (0.2 ± 0.5% vs. 2.1 ± 3.5%, P = 0.041).

CONCLUSION

BBP significantly enhances atrial electromechanical synchrony and is associated with signals of favorable atrial remodeling and a lower long-term atrial arrhythmia burden compared to conventional RAAP. These findings support BBP as a potentially preferable pacing strategy for SSS patients, though confirmation in larger, multicenter trials is needed.