Comparison between his-bundle pacing and left bundle branch pacing in patients with atrioventricular block.

BACKGROUND: Pacing the cardiac conduction system has been explored in patients with conduction system disease, but comprehensive comparisons between different pacing modalities are not well investigated.

OBJECTIVE: To compare pacing characteristics and ventricular synchrony between His-bundle pacing (HBP) and left bundle branch pacing (LBBP) in patients with atrioventricular block (AVB).

METHODS: Fifty pacemaker-indicated patients with AVB were enrolled. Twenty-five patients underwent HBP, and another 25 patients underwent LBBP. Success rate, procedural and fluoroscopy duration, pacing parameters, and echocardiographic data were perioperatively assessed and at 3-month follow-up.

RESULTS: HBP was successful in 19 of 25 (76.0%) patients, whereas LBBP was successful in 22 of 25 (88.0%) patients. Compared with HBP, LBBP capture threshold was significantly lower (0.76 ± 0.25 V/0.4 ms vs. 1.27 ± 0.61 V/1.0 ms, P = 0.003) and R-wave amplitude was significantly higher with LBBP (11.7 ± 6.6 vs. 4.9 ± 2.4 mV, P < 0.001) at implant. The mean procedural time (74.3 ± 17.8 vs. 63.2 ± 12.3 min, P = 0.029) and fluoroscopy duration (10.3 ± 4.5 vs. 6.8 ± 2.2 min, P = 0.005) were significantly longer in the HBP group compared to LBBP. At 3-month follow-up, pacing capture threshold remained more stable in LBBP than in HBP group while left ventricular synchrony was similar between both groups.

CONCLUSION: Despite similar impact on ventricular synchrony compared with HBP, LBBP featured a significantly lower pacing capture threshold, higher R-wave amplitude, and less time to achieve similar success rate in patients with AVB. These findings indicate LBBP as a physiological pacing strategy for AVB patients.