Study Limitations
There are some limitations in this study. Firstly, our study was an observational study with a small sample size. Secondly, we only compared the changes of QRS duration on the twelve‐lead surface EGM, which should be further studied by using the mapping electrode catheter. Thirdly, we did not explore the effect of output voltage of LBBP on the paced QRSd in detail. However, the pQRSd narrowing caused by LBBP is evident in patients with RBBB, and the specific mechanisms behind this may be multifactorial, which requires more precise mapping of the propagation and further anatomical study of the conduction system of the heart.
This work was supported by research grant No. 3502Z20174005 from Huimin Project of Xiamen Municipal Bureau of Science and Technology.