Background: Left bundle branch pacing (LBBP) is a novel pacing method and has been observed to have low and stable pacing thresholds in prior small short-term studies. The objective of this study was to evaluate the feasibility and safety of LBBP in a large consecutive diverse group of patients with long-term follow-up. Methods: This study prospectively enrolled 632 consecutive pacemaker patients with attempted LBBP from April 2017 to July 2019. Pacing parameters, complications, ECG, and echocardiographic measurements were assessed at implant and during follow-up of 1, 6, 12, and 24 months. Results: LBBP was successful in 618/632 (97.8%) patients according to strict criteria for LBB capture. Mean follow-up time was 18.6±6.7 months. Two hundred thirty-one patients had follow-up over 2 years. LBB capture threshold at implant was 0.65±0.27 mV at 0.5 ms and 0.69±0.24 mV at 0.5 ms at 2-year follow-up. A significant decrease in QRS duration was observed in patients with left bundle branch block (167.22±18.99 versus 124.02±24.15 ms, P <0.001). Postimplantation left ventricular ejection fraction improved in patients with QRS≥120 ms (48.82±17.78% versus 58.12±13.04%, P 3 V or loss of bundle capture in 6 patients (1%), 2 patients of them had a loss of conduction system capture. Two patients required lead revision due to dislodgement. Conclusions: This large observational study suggests that LBBP is feasible with high success rates and low complication rates during long-term follow-up. Therefore, LBBP appears to be a reliable method for physiological pacing for patients with either a bradycardia or heart failure pacing indication.

For patients with atrial fibrillation, the use of oral anticoagulant therapy to prevent stroke is limited by the risk of bleeding. Left atrial appendage closure is considered for patients who are unsuitable candidates for long-term anticoagulation, but its role in patients who are eligible for anticoagulants has not been established. In this ongoing, prospective, international, randomized trial involving patients with atrial fibrillation who were suitable candidates for anticoagulation, we randomly assigned patients in a 1:1 ratio to receive either device-based left atrial appendage closure (device group) or non-vitamin K antagonist oral anticoagulant (NOAC) therapy (anticoagulation group). The primary efficacy end point - a composite of death from cardiovascular causes, stroke, or systemic embolism - was tested for noninferiority (noninferiority margin, 4.8 percentage points) after 3 years of follow-up. The primary safety end point, non-procedure-related bleeding, was tested for superiority. Of the 3000 patients who underwent randomization, 1499 were assigned to the device group and 1501 to the anticoagulation group. The mean (±SD) age of the patients was 71.7±7.5 years, 31.9% of the patients were women, and the mean CHA₂DS₂-VASc score was 3.5±1.3. At 3 years, a primary efficacy end-point event had occurred in 81 patients (Kaplan-Meier estimate, 5.7%) in the device group and in 65 patients (Kaplan-Meier estimate, 4.8%) in the anticoagulation group (difference, 0.9 percentage points; 95% confidence interval [CI], -0.8 to 2.6; P<0.001 for noninferiority). Non-procedure-related bleeding occurred in 154 patients (Kaplan-Meier estimate, 10.9%) in the device group and in 260 patients (Kaplan-Meier estimate, 19.0%) in the anticoagulation group (hazard ratio, 0.55; 95% CI, 0.45 to 0.67; P<0.001 for superiority). Among patients with atrial fibrillation who were candidates for anticoagulation, device-based left atrial appendage closure was noninferior to NOAC therapy with respect to a composite of death from cardiovascular causes, stroke, or systemic embolism and was superior to NOAC therapy for non-procedure-related bleeding at 3 years. (Funded by Boston Scientific; CHAMPION-AF ClinicalTrials.gov number, NCT04394546.).