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. 231 patients had follow-up over 2 years. LBB capture threshold at implant was 0.65±0.27 mV@0.5ms and 0.69±0.24 mV@0.5ms at 2-year follow-up. A significant decrease in QRS duration was observed in patients with LBBB (167.22 ± 18.99ms vs. 124.02 ± 24.15ms, p<0.001). Post implantation left ventricular ejection fraction improved in patients with QRS≥120ms (48.82±17.78 % vs. 58.12±13.04 %, p<0.001). The number of patients with moderate and severe tricuspid regurgitation decreased at 1-year. Permanent right bundle branch injury occurred in 55 (8.9%) patients. LBB capture threshold increased to more than 3 V or loss of bundle capture in 6 patients (1%), 2 patients of them had 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.

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Background Persistent atrial fibrillation may lead to a higher probability of inappropriate shocks in heart failure patients with an implantable cardioverter‐defibrillator ( ICD ). The aim of this study was to evaluate the impact of His‐Purkinje conduction system pacing combined with atrioventricular node ablation in improving heart function and preventing inappropriate shock therapy in these patients. Methods and Results A total of 86 consecutive patients with persistent atrial fibrillation and heart failure who had indications for ICD implantation were enrolled from January 2010 to March 2018. His‐Purkinje conduction system pacing with ICD and atrioventricular node ablation was attempted in 55 patients, and the remaining patients underwent ICD implantation only. Left ventricular (LV) ejection fraction, LV end‐systolic volume, New York Heart Association ( NYHA ) classification, shock therapies, and drug therapy were assessed during follow‐up. Overall, 31 patients received ICD implantation with optimal drug therapy (group 1). atrioventricular node ablation combined with His‐Purkinje conduction system pacing was successfully achieved in 52 patients (group 2). During follow‐up, patients in group 2 had lower incidence of inappropriate shock (15.6% versus 0%, P <0.01) and adverse events ( P =0.011). Meanwhile, improvement in LV ejection fraction and reduction in LV end‐systolic volume were significantly higher in group 2 than in group 1 (15% versus 3%, P <0.001; and 40 versus 2 mL, P <0.01, respectively). NYHA functional class improved in both groups from a baseline 2.57±0.68 to 1.73±0.74 in group 1 and 2.73±0.59 to 1.42±0.53 in group 2 ( P <0.01). Conclusions His‐Purkinje conduction system pacing combined with atrioventricular node ablation is feasible and safe with a high success rate in persistent atrial fibrillation patients with heart failure and ICD indication. It can significantly reduce the incidence of inappropriate shocks and improve LV function.

Aims His-bundle pacing (HBP) combined with atrioventricular node (AVN) ablation has been demonstrated to be effective in patients with atrial fibrillation (AF) and heart failure (HF) during medium-term follow-up and there are limited data on the risk analysis of adverse prognosis in this population. In this study, we aimed to evaluate the long-term performance of HBP following AVN ablation in AF and HF. Methods and results From August 2012 to December 2017, consecutive AF patients with HF and narrow QRS who underwent AVN ablation and HBP were enrolled. The clinical and echocardiographic data, pacing parameters, all-cause mortality, and heart failure hospitalization (HFH) were tracked. A total of 94 patients were enrolled (age 70.1 ± 10.5 years; male 57.4%). Acute HBP were achieved in 89 (94.7%) patients with successful permanent HBP combined with AVN ablation in 81 (86.2%) patients. Left ventricular ejection fraction (LVEF) improved from 44.9 ± 14.9% at baseline to 57.6 ± 12.5% during a median follow-up of 3.0 (IQR: 2.0–4.4) years (P &lt; 0.001). Heart failure hospitalization or all-cause mortality occurred in 21 (25.9%) patients. The LVEF ≤ 40%, pulmonary artery systolic pressure (PASP) ≥40 mmHg, or serum creatinine (Scr) ≥97 μmol/L at baseline was significantly associated with higher composite endpoint of HFH or death (P &lt; 0.05). The His capture threshold was 1.0 ± 0.7 V/0.5 ms at implant and remained stable during follow-up. Conclusion His-bundle pacing combined with AVN ablation was effective in patients with AF and drug-refectory HF. High PASP, high Scr, or low LVEF at baseline was independent predictors of composite endpoint of all-cause mortality or HFH.

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Case report A 74-years-old man who received a dual-chamber pacemaker with right ventricular (RV) septal pacing due to advanced atrioventricular (AV) block 6 years ago developed a RV pacing-induced cardiomyopathy with left ventricular ejection fraction (LVEF) of 34% and a left ventricular end-diastolic diameter (LVEDd) of 62 mm. We decided to upgrade the RV pacing to a conduction system pacing. Electrograms obtained from the pacing lead at the His-bundle revealed AV nodal disease with progressive prolongation of A-H interval with dropped His and complete infra-Hisian AV block with dissociation of His and ventricular electrograms (Figure 1A). Pacing at this site Published on behalf of the European Society of Cardiology. All rights reserved.

Aims His-Purkinje conduction system pacing (HPCSP) utilizing His (HBP) or left bundle branch pacing (LBBP) in patients with atrial fibrillation (AF) and wide QRS duration has not been well studied. We assessed the benefit of left bundle branch block (LBBB) correction during HPCSP in AF patients undergoing atrioventricular junction (AVJ) ablation with LBBB, compared with those with narrow QRS duration. Methods and results This is an observational study in consecutive patients with typical LBBB or narrow QRS duration in whom we attempted HPCSP after AVJ ablation for refractory AF with a left ventricular ejection fraction (LVEF) ≤ 50%. Echocardiographic responses and clinical outcomes were assessed at baseline and during 1 year of follow-up. A total of 178 patients were enrolled, of which 170 achieved AVJ ablation + permanent HPCSP (age 69.3 ± 10.1 years; LVEF 34.3 ± 7.7%), 133 (78.2%) patients had a narrow QRS duration, and 37 (21.2%) had an LBBB. The QRS duration changed from a baseline of 159.7 ± 16.6 ms to a paced QRS duration of 110.4 ± 12.7 ms in the LBBB cohort and from 95.6 ± 10.4 to 100.8 ± 14.5 ms (both P < 0.001) in the narrow QRS cohort after AVJ ablation and pacing. Compared with the narrow QRS cohort, the LBBB cohort showed a greater absolute increase in LVEF (+22.3% vs. +14.2%, P < 0.001), higher super responder rate (71.4% vs. 49.2%, P = 0.011), and greater New York Heart Association (NYHA) class improvement (À1.9 vs. À1.4, P < 0.001) at 1 year. Conclusion Patients with LBBB have greater improvement in LVEF and NYHA class function than patients with narrow QRS from HPCSP after AVJ ablation.

BACKGROUND: Left bundle branch pacing (LBBP) has emerged as a promising pacing modality to preserve physiological left ventricular activation; however, prospective data evaluating its long-term safety and efficacy in pacemaker-dependent patients following atrioventricular junction (AVJ) ablation are lacking. This study aimed to examine the feasibility, safety, and efficacy of LBBP in patients with atrial fibrillation and heart failure (HF) after AVJ ablation and compare LBBP with His bundle pacing (HBP) through a propensity score (PS) matching analysis. METHODS: We prospectively enrolled patients with atrial fibrillation and HF referred for AVJ ablation and LBBP between July 2017 and December 2019. The control group was patients selected from HBP implants performed from 2012 to 2019 using PS matching with a 1:1 ratio. RESULTS: A total of 99 patients were enrolled in the study. The LBBP implant success rate was 100%. Left ventricular ejection fraction improved from baseline 30.3±4.9 to 1-year 47.3±14.5 in HF patients with reduced ejection fraction and from baseline 56.3±12.1 to 1-year 62.3±9.1 in HF patients with preserved ejection fraction (both P <0.001), and left ventricular ejection fraction in both groups remained stable for up to 3 years of follow-up. A threshold increase >2 V at 0.5 ms occurred in only one patient. Of 176 (81.9%) of 215 patients who received permanent HBP post-AVJ ablation, 86 were matched to the LBBP group by 1:1 PS (propensity score matched His bundle pacing, N=86; propensity score matched left bundle branch pacing, N=86). No significant differences in echocardiographic or clinical outcomes were observed between the 2 groups ( P >0.05), whereas lower thresholds, greater sensed R-wave amplitudes, and fewer complications were observed in the propensity score matched left bundle branch pacing group ( P <0.05). CONCLUSIONS: LBBP is feasible, safe, and effective in patients with atrial fibrillation and HF post-AVJ ablation and has similar clinical benefits, a higher implant success rate, better pacing parameters, and fewer complications compared with HBP.