Abstract 13982: Evaluation of Electrocardiographic and Intracardiac Electrogram Characteristics for Response to His-Purkinje Conduction System Pacing in Patients With Left Bundle Branch Block Corrected by His Bundle Pacing

Abstract

Introduction: His-Purkinje conduction system pacing (HPCSP), including His bundle pacing (HBP) and left bundle branch pacing has been proved to improve clinical outcomes in patients with left bundle branch block (LBBB) and heart failure. However, some patients still remain non-responsive to HPCSP. We aimed to evaluate the effect of electrocardiographic and intracardiac electrogram characteristics for response to HPCSP in patients with typical LBBB which could be corrected by HBP. Methods: Consecutively enrolled patients with typical LBBB and baseline LVEF ≤40% from January 2012 to June 2020 who were able to achieve LBBB correction during HBP and implanted HPCSP. Baseline QRS duration, paced QRS duration, ΔQRSd, H-QRSend and ΔQRSend/H-QRSend were measured during the implantation. A 1-year absolute increase in LVEF≥15% identified super-response to HPCSP. Results: A total of 123 patients were included in the study (mean age 68.2±10.6 years; male 52.0%). Baseline characteristics of patients with ΔLVEF≥15% (N=93) and ΔLVEF<15% (N=30) were comparable except for larger ΔQRSend/H-QRSend (0.42±0.07 vs 0.35±0.08 ms, p<0.001), smaller baseline QRS duration (161.9±15.5 vs 172.3±17.4 ms, p=0.002) and paced QRS duration (100.9±14.9 vs 110.5±13.4 ms, p=0.002) in patients with ΔLVEF≥15%. Receiver-operating characteristic curve analysis demonstrated that a cut-off value of 0.39 for ΔQRSend/H-QRSend presented a sensitivity of 77% and specificity of 76% (AUC=0.776) to predict super-response to HPCSP. At multivariate analysis, larger ΔQRSend/H-QRSend, smaller paced QRS duration and baseline QRS duration remained predictors of super-response after HPCSP. Conclusions: HPCSP delivers favorable echocardiographic response in typical LBBB corrected by HBP. A larger ΔQRSend/H-QRSend, smaller baseline QRS duration and paced QRS duration are associated with a better response after HPCSP. ΔQRSend/H-QRSend is a novel and important predictor of LVEF increase.