1 INTRODUCTION
Currently, the pacing methods mainly used in clinical treatment include right ventricular pacing (RVP), His bundle pacing (HBP) and LBBAP. Among them, LBBAP is a new physiological pacing method that can effectively narrow the width of the QRS wave, synchronize mechanical contraction of the left ventricular myocardium, improve cardiac function, and overcome atrial fibrillation defects and heart failure caused by RVP pacing[1]. However, LBBAP electrodes should permeate from the right ventricular septum to the left ventricular septum subendocardium. Therefore, there is a potential risk of damaging the coronary arteries and veins, such as the ventricular septal, the left anterior descending branch (LAD), the right posterior coronal descending branch (PD) and the left posterior ventricular branch (PL) during the implantation of LBBAP electrodes. Furthermore, during the LBBAP procedure, Qi P et al.[2] found that the pacemaker electrode penetrated the interventricular septal vessels which were successfully visualized upon injecting the contrast medium into the C315 His sheath. In the previous reports, pacemakers implanted in the interventricular septum can damage the anterior descending artery or interventricular septal artery. For example, some studies have found that ventricular septal pacing electrodes can compress the anterior descending artery to different degrees, resulting in different degrees of myocardial infarction[3-6]. However, to our knowledge, there are no studies concerning LBBAP electrodes and coronary vascular injury. Therefore, this study aimed to evaluate the risk of intraoperative coronary injury by measuring the adjacency relationship between the tip of LBBAP electrodes and the coronary arteries to provide a reliable clinical reference for the safe implantation of the LBBAP.