Clinical Outcomes of Selective Versus Nonselective His Bundle Pacing.

OBJECTIVES: The aim of the study was to evaluate the clinical outcomes of nonselective (NS) His bundle pacing (HBP) compared with selective (S) HBP. BACKGROUND: 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. METHODS: 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 3 months 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. RESULTS: 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. CONCLUSIONS: NS-HBP was associated with similar outcomes of death or heart failure hospitalization when compared with S-HBP. Multicenter risk-matched clinical studies are needed to confirm these findings.

Clinical Outcomes of His Bundle Pacing Compared to Right Ventricular Pacing.

BACKGROUND: Right ventricular pacing (RVP) is associated with heart failure and increased mortality. His bundle pacing (HBP) is a physiological alternative to RVP. OBJECTIVES: This study sought to evaluate clinical outcomes of HBP compared to RVP. METHODS: All patients requiring initial pacemaker implantation between October 1, 2013, and December 31, 2016, were included in the study. Permanent HBP was attempted in consecutive patients at 1 hospital and RVP at a sister hospital. Implant characteristics, all-cause mortality, heart failure hospitalization (HFH), and upgrades to biventricular pacing (BiVP) were tracked. Primary outcome was the combined endpoint of death, HFH, or upgrade to BiVP. Secondary endpoints were mortality and HFH. RESULTS: HBP was successful in 304 of 332 consecutive patients (92%), whereas 433 patients underwent RVP. The primary endpoint of death, HFH, or upgrade to BiVP was significantly reduced in the HBP group (83 of 332 patients [25%]) compared to RVP (137 of 433 patients [32%]; hazard ratio [HR]: 0.71; 95% confidence interval [CI]: 0.534 to 0.944; p = 0.02). This difference was observed primarily in patients with ventricular pacing >20% (25% in HBP vs. 36% in RVP; HR: 0.65; 95% CI: 0.456 to 0.927; p = 0.02). The incidence of HFH was significantly reduced in HBP (12.4% vs. 17.6%; HR: 0.63; 95% CI: 0.430 to 0.931; p = 0.02). There was a trend toward reduced mortality in HBP (17.2% vs. 21.4%, respectively; p = 0.06). CONCLUSIONS: Permanent HBP was feasible and safe in a large real-world population requiring permanent pacemakers. His bundle pacing was associated with reduction in the combined endpoint of death, HFH, or upgrade to BiVP compared to RVP in patients requiring permanent pacemakers.