Abstract 12377: Differing Response to Left Bundle Branch Area Pacing versus Biventricular Pacing for Cardiac Resynchronization According to Septal Scar Burden Among Nonischemic Cardiomyopathy Patients

Abstract

Introduction: Whether left bundle branch area pacing (LBBAP) have similar benefit compared with biventricular pacing (BVP) for cardiac resynchronization therapy (CRT) in nonischemic cardiomyopathy (NICM) with different septal scar burden is still unknown. Hypothesis: We hypothesize that a higher septal scar burden might attenuate the relative benefits of LBBAP versus BVP. Aims: This study aims to assess the effect of the septal scar on the response to LBBAP and BVP for CRT. Methods: We retrospectively included nonischemic cardiomyopathy (NICM) patients with wide QRS complex and CRT indications who underwent pre-procedure cardiac magnetic resonance (CMR) examination and received either BVP or LBBAP. Late gadolinium enhancement (LGE) was analyzed for scar quantification. CRT response was defined as an absolute increase of≥ 5% in left ventricular ejection fraction (LVEF) at 6 months follow-up. Results: A total of 147 patients were included. Fifty-one patients (34.7%) had LBBAP, and 96 (65.3%) had BVP. As septal LGE extent increased, LVEF improvement at 6-month follow-up gradually decreased in the BVP group whereas dropped sharply in the LBBAP group. The nonlinear inverse relationship between the relative benefit of LBBAP versus BVP for response and septal LGE extent, as well as cut-off points (4.4%, 13.3%) of septal LGE extent, were determined using a restricted cubic spline model. Among patients with low septal scar extent (<4.4%), LBBAP was associated with higher response odds than BVP [Odds Ratio (OR) 3.87,95% confidence interval (CI): 0.99-15.17,p=0.052]. In the medium septal scar extent (4.4%-13.3%) group, response odds did not differ between LBBAP and BVP (OR 2.00,95%CI: 0.41-9.74, p=0.391). Among patients with high septal scar extent (>13.3%), BVP was associated with higher response odds (OR 0.12, 95%CI: 0.03-0.54, p=0.006). Conclusions: Response to LBBAP and BVP among NICM patients might be impacted by septal scar burden.