Clinical Outcomes of Selective Versus Nonselective His Bundle Pacing

Abstract

The aim of the study was to evaluate the clinical outcomes of nonselective (NS) His bundle pacing (HBP) compared with selective (S) HBP. HBP is the most physiologic form of ventricular pacing. NS-HBP results in right ventricular septal pre-excitation due to fusion with myocardial capture in addition to His bundle capture resulting in widened QRS duration compared with S-HBP wherein there is exclusive His bundle capture and conduction. The Geisinger and Rush University HBP registries comprise 640 patients who underwent successful HBP. Our study population included 350 consecutive patients treated with HBP for bradyarrhythmic indications who demonstrated≥20% ventricular pacing burden 3months post-implantation. Patients were categorized into S-HBP or NS-HBP based on QRS morphology (NS-HBP n= 232; S-HBP n= 118) at the programmed output at the 3-month follow-up. The primary analysis outcome was a combined endpoint of all-cause mortality or heart failure hospitalization. The NS-HBP group had a higher number of men (64% vs. 50%; p= 0.01), higher incidence of infranodal atrioventricular block (40% vs. 9%; p<0.01), ischemic cardiomyopathy (24% vs. 14%; p= 0.03), and permanent atrial fibrillation (18% vs. 8%; p= 0.01). The primary endpoint occurred in 81 of 232 patients (35%) in the NS-HBP group compared with 23 of 118 patients (19%) in the S-HBP group (hazard ratio: 1.38; 95% confidence interval: 0.87 to 2.20; p= 0.17). Subgroup analyses of patients at greatest risk (higher pacing burden or lower left ventricular ejection fraction) revealed no incremental risk with NS-HBP. NS-HBP was associated with similar outcomes of death or heart failure hospitalization when comparedwith S-HBP. Multicenter risk-matched clinical studies are needed to confirm these findings.