The flexibility of delayed fluoroscopic left ventricular angiography in periprocedural real-time visualization of the lead tip in left bundle branch pacing.

BACKGROUND: Current electrocardiography and electrogram (EGM) criteria for confirming left bundle branch (LBB) capture may be inconclusive in certain clinical scenarios. Real-time imaging methods to evaluate lead positioning during LBB pacing (LBBP) remain limited. OBJECTIVE: This study aimed to evaluate the feasibility of delayed fluoroscopic left ventricular (LV) angiography (LVG) for real-time visualization of lead position during LBBP. METHODS: Patients undergoing LBB area pacing with delayed LVG were classified as LBBP or LV septal pacing (LVSP) according to EGM-based capture criteria. LBB capture was identified by fascicular potentials, morphology transitions, or a stepwise electrocardiography/EGM algorithm; lead tip-to-LV and right ventricular septal border distances were measured at end-systole and end-diastole, with right ventricular distance representing total lead insertion length. RESULTS: 76 patients were included (LBBP n = 51; LVSP n = 25). Pacing threshold, impedance, R-wave amplitude, and stimulus-to-V6 LV activation time did not differ significantly between the groups. The QRS onset to V6 LV activation time was shorter in the LBBP group than the LVSP group (33.3 ± 10.6 ms vs 41.4 ± 12.9 ms; P < .05). Delayed LVG demonstrated significantly shorter lead tip-to-LV septal border distances in the LBBP group at both end-diastole (0.93 ± 0.35 mm vs 2.12 ± 0.90 mm) and end-systole (0.87 ± 0.42 mm vs 2.01 ± 0.99 mm; both P < .001), with greater lead insertion depth observed in the LBBP group (13.4 ± 1.2 mm vs 12.9 ± 0.9 mm; P < .05, at end-diastole). No contrast-related renal complications were noted. CONCLUSION: Delayed LVG provides a practical intraprocedural imaging method as an adjunct for real-time visualization of lead position during LBBP, particularly when capture criteria are uncertain.