Left bundle branch pacing is superior in preserving ventricular mechanical synchrony and cardiac function than right ventricular pacing: a two-center experience

Background

Left bundle branch pacing (LBBP) has emerged as a novel pacing modality. Although it has been proved to maintain electrical synchrony better than right ventricular pacing (RVP), little is known about the impact on mechanical synchrony. This study investigates if LBBP preserves mechanical synchrony and cardiac function better compared to conventional (CRVP) and leadless (LRVP) RVP.

Methods

Sixty-five patients with pacing indication for bradycardia were prospectively enrolled: Twenty-two were treated with LBBP, 23 with CRVP and 20 with LRVP. All patients underwent echocardiography before and after implantation and at one-year follow-up. Left ventricular (LV) volumes, ejection fraction (EF) and global longitudinal strain (GLS) were measured. Regional septal (SW) and lateral wall work (LW) was calculated as the average from the respective basal and mid-ventricular segments in the apical four-chamber and three-chamber view. The lateral-septal work difference (LSWD) was used as a measure of mechanical dyssynchrony.

Results

At baseline, the QRS duration and LSWD were similar in all three groups. During follow-up, the QRS duration increased least in LBBP compared to CRVP and LRVP (+28.1±18.3ms vs +58.2±31.4 and 47.1±26.1ms, both P<0.01). SW was markedly decreased in CRVP and LRVP while LW work remained unchanged, resulting in a large LSWD compared to LBBP (1308.4±732.9 mmHg*% and 1451.3±606.1 mmHg*% vs. 286.0±479.9mmHg*%, both P<0.001). During one year follow-up, LVEF and LV GLS decreased more in CRVP compared to LBBP (both P<0.05).

Conclusion

LBBP causes less LV dyssynchrony than CRVP and LRVP as it preserves a more physiologic conduction pattern. With this, LBBP appears to preserve LV function better than CRVP. CRVP and LRVP did not differ in mechanical dyssynchrony or LV remodelling.

Funding Acknowledgement

Type of funding sources: None.