Clinical Outcomes and Electrophysiological Characteristics of Partial Perforation After Left Bundle Branch Area Pacing.

Background: Septal perforation, defined as partial or complete protrusion of a lead helix, is a potential complication of left bundle branch area pacing, theoretically increasing risks of pacing failure and thromboembolism. However, no studies have examined the long-term prognosis of patients with partial perforations (PPs).

Objectives: This study aimed to elucidate the incidence, outcomes, and electrophysiological characteristics of PP in clinical and experimental swine studies.

Methods: Patients requiring pacing who underwent successful left bundle branch area pacing were retrospectively included. PP was identified using postoperative echocardiography. Clinical outcomes, including all-cause mortality, thromboembolism, and lead-related complications, were compared between the PP and non-PP groups. Waveforms from the nonfiltered unipolar electrogram (NF-EGM) recorded at the lead tip were evaluated to identify morphology specific to PP.

Results: Of the 95 patients, PP was confirmed in 25 (26.3%), occurring only in patients with left bundle branch capture, with an incidence rate of 41.7%. Event-free survival rates were comparable between the PP and non-PP groups at a median follow-up of 24 months (log rank, P = 0.298). No thromboembolisms or lead-related complications occurred in the PP group. The type-QS and type-R morphologies of NF-EGM reliably identified and excluded PP, respectively, as validated in swine heart experiments.

Conclusions: This study found that PP is not associated with an increased risk of adverse clinical outcomes. Deep septal lead deployment utilizing the NF-EGM morphology would be useful in recognizing and avoiding PP intraoperatively.