Limitations
First, this is a retrospective study with small sample size, a prospective study with larger sample size is needed to confirm the finding. Besides, this study is lack of directly comparison between the LBBAP and right ventricular pacing on the FTR. Second, we did not differentiate LBBP from LVSP. However, LVSP was supposed to have the same effect as LBBP[32]. Third, dimensions of the tricuspid annulus, peak tricuspid regurgitation jet velocity, the right atrial pressure and other parameters were crucial for assessing the right ventricular and TV performance. However, it is time consuming to acquire these parameters in daily work. As a retrospective study, these data were not recorded and difficult to trace. Finally, the mean HR of LBBAP was 65.4bpm, a higher HR (such as 70bpm) may result in a better outcome, which should be demonstrated in the future.