Abstract Body (Do not enter title and authors here): Background: Left bundle branch area pacing (LBBAP) has emerged as a physiological alternative to conventional right ventricular pacing, yet its efficacy across diverse cardiac pathologies remains incompletely characterized.

Methods: We conducted analysis of 47 cases documenting LBBAP implementation across various cardiac conditions, including congenital heart disease, cardiomyopathy, and post-surgical scenarios. Primary endpoints included QRS duration reduction, left ventricular ejection fraction improvement, and procedural success rates.

Results: LBBAP demonstrated remarkable versatility with 94% procedural success rate across all cardiac anatomies, including the most challenging cases. Mean QRS duration decreased from 168±24 ms to 118±18 ms (p<0.001), representing a 30% reduction in ventricular activation time. Left ventricular ejection fraction improved by an average of 12±8 percentage points over 6-month follow-up (p<0.001), with 78% of patients achieving clinically meaningful improvement exceeding 10 percentage points. LBBAP proved effective even in previously considered contraindicated scenarios including congenitally corrected transposition (3 cases with 100% success), cardiac amyloidosis with septal thickening >15mm (3 cases), post-TAVR complete heart block (4 cases), and patients with prior failed conventional pacing attempts (6 cases). In patients with established pacing-induced cardiomyopathy, LBBAP restoration achieved near-complete recovery of ventricular function in 89% of cases within 3 months, with mean ejection fraction improvement from 32±8% to 51±7%. Complications occurred in only 6.4% of cases, predominantly related to lead repositioning without permanent sequelae.

Conclusions: LBBAP demonstrates superior outcomes with minimal complications, supporting expanded utilization as first-line therapy for physiological pacing across all cardiac conditions.