Safety assessment of coronary arteries during left bundle branch area pacing.

BACKGROUND

This study aimed to assess the safety of left bundle branch area pacing (LBBAP) by measuring the distance from the tip of the electrode to the nearby coronary artery with a nine-partition grid method.

METHODS

From January 2019 to October 2020, patients who underwent LBBAP and postoperative coronary angiography in the Second Affiliated Hospital of Nanchang University were included in the study. The patients' fluoroscopic images of LBBAP and coronary angiography were collected and analyzed. Changes in the ST‑T segment in the electrocardiogram (ECG), serum troponin, and myocardial enzyme profiles were observed before and after the LBBAP procedure.

RESULTS

A total of 50 patients were included in this study, of whom 46 patients underwent implantation with a pacemaker and 4 patients received an implantable cardioverter defibrillator (ICD). The pacing electrodes were confined to the posterior-middle (PM), median (M), Posterior inferior (PI), and middle inferior (MI) positions of the two-dimensional nine-square grid or in the junction area of the above positions, and were concentrated in the rectangle formed by the line of the center points of the four positions. The average vertical distances from the electrode tip to the left anterior descending branch artery (LAD), posterior descending branches (PD) and the left posterior ventricular branches (PL) were 19.69 ± 8.72 mm, 26.09 ± 8.02 mm, and 21.11 ± 7.86 mm, respectively; the minimum was 5.28 mm, 9.51 mm, and 8.69 mm, respectively. Coronary angiography in all patients showed no significant injury to the ventricular septal branch; however, we observed elevated serum troponin and changes in ST‑T segment in ECG.

CONCLUSION

The study demonstrates that pacing electrodes in LBBAP can be safely implanted over a wide range. Coronary arteries are likely to be safe when the pacing electrodes are located within the rectangle formed by the line connecting the PM, M, PI, and MI zone centroids. The left bundle branch can be quickly captured and the safety of the coronary artery can be improved by locating the electrode in the posterior-mid zone. The potential risk of injury to the LAD from the electrode is greater compared with the PD.