Use of acoustic cardiography to assess left ventricular electromechanical synchronization during left bundle branch pacing

Xianhao Wu; Wei Hu; Lei Song; Wanlan Chen; Yi Zhou; Lihong Zhou; Ziming Ou; Zhaohui Qiu

doi:10.1016/j.hroo.2023.08.009

Use of acoustic cardiography to assess left ventricular electromechanical synchronization during left bundle branch pacing

Heart Rhythm O2. 2023 Sep 11;4(10):632-640. doi: 10.1016/j.hroo.2023.08.009. eCollection 2023 Oct.

Authors

Xianhao Wu¹, Wei Hu¹, Lei Song¹, Wanlan Chen¹, Yi Zhou¹, Lihong Zhou¹, Ziming Ou¹, Zhaohui Qiu¹

Affiliation

¹ Department of Cardiology, Shanghai Tong Ren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.

Abstract

Background: Left bundle branch pacing (LBBP) is a physiological pacing that captures the main left bundle or its proximal branch. Electromechanical activation time (EMAT) is an acoustic cardiographic metric that provides a simple method for evaluating left ventricular (LV) synchrony. Prolonged EMAT reflects impaired LV electromechanical coupling.

Objective: The purpose of this study was to explore whether EMAT can confirm that LBBP produces more satisfactory LV electromechanical synchronization than conventional right ventricular pacing modalities.

Methods: Patients with standard pacing indications and narrow QRS duration were recruited for this study. Unipolar pacing under 3 different modalities-right ventricular apical pacing (RVAP), right ventricular high septal pacing (RVHSP), and LBBP-were successively performed in each patient. Pacing parameters, echocardiographic characteristics, and acoustic cardiographic parameters at different pacing modalities and during normal rhythm were collected.

Results: A total of 55 patients were enrolled, and all had successful LBBP. Left ventricular activation time (LVAT) was significantly associated with EMAT, with LVAT vs EMAT correlation coefficient of 0.665 (P <.001). LVAT during LBBP was shorter than that during RVHSP (51.93 ± 2.732 ms vs 85.59 ± 2.240 ms; P <.001). EMAT of LBBP was significantly lower than either RVAP or RVHSP (95.44 ± 1.794 ms vs 143.32 ± 2.376 ms, and 132.22 ± 1.872 ms; both P <.001) but was similar to that of intrinsic rhythm (95.37 ± 2.271 ms; P = .862).

Conclusion: We found EMAT significantly prolonged in RVHSP and RVAP but not in the LBBP mode. This finding indicates superior electromechanical synchronization in patients having LBBP. EMAT measurement could be an additional method for identifying the ideal pacing position.

Keywords: Acoustic cardiography; Electromechanical activation time; Electromechanical synchronization; Left bundle branch pacing; Right ventricular pacing.