LOCAlizaTion and clinical corrElation of Left Bundle Branch Pacing lead: Insights from a computed tomographic angiography (LOCATE LBBP) study.

BACKGROUND

Left bundle branch pacing (LBBP) provides physiological activation with stable pacing parameters. However, there is a paucity of data on direct assessment of lead stability.

OBJECTIVES

The purpose of this study was to assess the stability of an LBBP lead using computed tomographic angiography (CTA) during medium-term follow-up and to correlate the anatomic location of the lead and electrophysiological characteristics of LBBP.

METHODS

Consecutive patients with successful LBBP using a lumenless lead were included. Patients without LBB capture, contrast allergy, and renal dysfunction were excluded. CTA was performed postimplantation and at 6 months. Primary endpoint was defined as consistent left bundle branch (LBB) capture with helix tip separated from the left ventricular (LV) blood pool by <2 mm by CTA at 6 months. Secondary endpoints were defined as loss of conduction system capture (LOCSC) or perforation with complete capture loss at 6 months.

RESULTS

Overall, 67 of 105 patients who underwent CTA after successful LBBP were included. Mean follow-up was 33.8 ± 4.4 months. Nonselective to selective capture transition was noted in 82% (n = 55). The lead remained stable at 6 months, with no difference in mean distance between LV blood pool and helix tip (-0.5 ± 1.8 mm vs -0.1 ± 2.1 mm; P = .23). Primary endpoint was achieved in 89.5% (n = 60). Consistent LBB capture (group I) at 6 months was noted in 94% (n = 63). LOCSC (group 2) was noted in 6% (n = 4) at 6 months. No perforation into the LV cavity with complete loss of capture was seen. Lead displacement by >2 mm away from the LV blood pool (sensitivity 100%; specificity 95%) and lack of nonselective to selective capture transition during implantation (odds ratio 18.0; 95% confidence interval 1.7-192.7; P = .01) were LOCSC predictors.

CONCLUSION

Deep septal deployment of the lead in the LV subendocardium for LBB capture is safe, with 94% of patients showing consistent conduction system capture during follow-up.