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Background: Left bundle branch area pacing (LBBAP) may be associated with greater improvement in left ventricular ejection fraction and reduction in death or heart failure hospitalization compared with biventricular pacing (BVP) in patients requiring cardiac resynchronization therapy. We sought to compare the occurrence of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and new-onset atrial fibrillation (AF) in patients undergoing BVP and LBBAP., Methods: The I-CLAS study (International Collaborative LBBAP Study) included patients with left ventricular ejection fraction ≤35% who underwent BVP or LBBAP for cardiac resynchronization therapy between January 2018 and June 2022 at 15 centers. We performed propensity score-matched analysis of LBBAP and BVP in a 1:1 ratio. We assessed the incidence of VT/VF and new-onset AF among patients with no history of AF. Time to sustained VT/VF and time to new-onset AF was analyzed using the Cox proportional hazards survival model., Results: Among 1778 patients undergoing cardiac resynchronization therapy (BVP, 981; LBBAP, 797), there were 1414 propensity score-matched patients (propensity score-matched BVP, 707; propensity score-matched LBBAP, 707). The occurrence of VT/VF was significantly lower with LBBAP compared with BVP (4.2% versus 9.3%; hazard ratio, 0.46 [95% CI, 0.29-0.74]; P <0.001). The incidence of VT storm (>3 episodes in 24 hours) was also significantly lower with LBBAP compared with BVP (0.8% versus 2.5%; P =0.013). Among 299 patients with cardiac resynchronization therapy pacemakers (BVP, 111; LBBAP, 188), VT/VF occurred in 8 patients in the BVP group versus none in the LBBAP group (7.2% versus 0%; P <0.001). In 1194 patients with no history of VT/VF or antiarrhythmic therapy (BVP, 591; LBBAP, 603), the occurrence of VT/VF was significantly lower with LBBAP than with BVP (3.2% versus 7.3%; hazard ratio, 0.46 [95% CI, 0.26-0.81]; P =0.007). Among patients with no history of AF (n=890), the occurrence of new-onset AF >30 s was significantly lower with LBBAP than with BVP (2.8% versus 6.6%; hazard ratio, 0.34 [95% CI, 0.16-0.73]; P =0.008). The incidence of AF lasting >24 hours was also significantly lower with LBBAP than with BVP (0.7% versus 2.9%; P =0.015)., Conclusions: LBBAP was associated with a lower incidence of sustained VT/VF and new-onset AF compared with BVP. This difference remained significant after adjustment for differences in baseline characteristics between patients with BVP and LBBAP. Physiological resynchronization by LBBAP may be associated with lower risk of arrhythmias compared with BVP., Competing Interests: Disclosures Dr Herweg is a speaker and consultant for Abbott; is a speaker and receives fellowship support from Medtronic. Dr Sharma has received honoraria from Medtronic and Biotronik, and is a consultant for Medtronic, Abbott, and Biotronik. Dr Cano has received honoraria from and is a consultant for Medtronic, Biotronik, and Boston Scientific. Dr Ponnusamy has received honoraria from Medtronic. Dr Zanon has received honoraria from Abbott, Biotronik, Boston Scientific, Medtronic, and Microport. Dr Jastrzebski has received honoraria and is a consultant for Medtronic and Abbott. Dr Chelu has received research support from Patient-Centered Outcomes Research Institute (PCORI), National Institutes of Health (NIH), Abbott, Impulse Dynamics, and an honorarium from Impulse Dynamics. Dr Vernooy has been a consultant for Biosense Webster, Philips, Medtronic, Abbott, and Boston Scientific; his institution has received research and educational grants from Philips, Abbott, Medtronic, and Biosense Webster. Dr Whinnett has received honoraria from Medtronic and Boston Scientific and is a consultant for Medtronic and Abbott. Dr Nair has received grants in aid from Biosense Webster, Medtronic Inc., CIHR, and Heart and Stroke Foundation of Canada, and honoraria and consulting fees from Medtronic, Biosense Webster, and Boston Scientific. Dr Curila is a consultant for and has received honoraria from Medtronic, Biotronik, and Abbott. Dr Subzposh has received honoraria from Medtronic. Dr Ellenbogen is a consultant for Medtronic, Boston Scientific, Abbott, and Biotronik, and has received honoraria from Medtronic, Boston Scientific, and Biotronik. Dr Vijayaraman has received honoraria and consultant, research, and fellowship support from Medtronic; he is a consultant for Abbott, Eaglepoint LLC, and has received honoraria from Boston Scientific, Biotronik, and holds a patent for a His bundle pacing delivery tool. The remaining authors report no conflicts of interest.

Background: Cardiac resynchronization therapy (CRT) using biventricular pacing (BVP) has been associated with greater clinical improvement in women than men. Recently, left bundle branch area pacing (LBBAP) has been shown to be an alternative form of CRT., Objectives: The purpose of this study was to investigate sex-specific outcomes for death and heart failure events in a large, international, multicenter, cohort of patients undergoing CRT with BVP or LBBAP., Methods: In this international study of 1,778 patients (575 female and 1203 male), sex-specific survival analysis was performed to compare the effect of LBBAP-CRT relative to BVP-CRT on the combined endpoint of death or heart failure hospitalization (HFH), and secondary endpoints of HFH only, and death alone., Results: Female patients were more likely to have nonischemic cardiomyopathy and left bundle branch block (LBBB) and less likely to have hypertension, diabetes, or coronary artery disease than were male patients. Overall, female patients had a better result with LBBAP compared with BVP than did male patients, with a significant 36% reduction in death or HFH (HR: 0.64; 95% CI: 0.43 to 0.97; P = 0.03) and a significant 60% reduction in HFH alone (HR: 0.4; 95% CI: 0.24 to 0.69, P < 0.01). Women had a greater reduction in death or HFH among those with nonischemic cardiomyopathy (HR: 0.45 95% CI: 0.26 to 0.79; P < 0.01) and LBBB (HR: 0.49; 95% CI: 0.27 to 0.87; P < 0.01). Sex-specific echocardiographic outcomes were better in women than in men., Conclusions: Women obtained significantly greater reductions in the combined endpoint of death or HFH (primarily driven by reduction in HFH) with LBBAP compared with BVP among patients requiring CRT than did men., Competing Interests: Funding Support and Author Disclosures Dr Subzposh has received honoraria from Medtronic. Dr Sharma has received honoraria from Medtronic; and has served as a consultant for Medtronic, Abbott, and Biotronik. Dr Cano has received honoraria from, and has served as a consultant for, Medtronic, Biotronik, and Boston Scientific. Dr Ponnusamy has received honoraria from Medtronic. Dr Herweg has served as a speaker and a consultant for Abbott; and has been a speaker for, and recipient of fellowship support from, Medtronic. Dr Zanon has received honoraria from Abbott, Biotronik, Boston Scientific, Medtronic, and Microport. Dr Jastrzebski has received honoraria from, and served as a consultant for, Medtronic and Abbott. Dr Chelu has received research support from PCORI, NIH, Abbott, Impulse Dynamics; and has received an honorarium from Impulse Dynamics. Dr Vernooy has served as a consultant for Biosense Webster, Philips, Medtronic, Abbott, and Boston Scientific; and his institution has received research and educational grants from Philips, Abbott, Medtronic, and Biosense Webster. Dr Whinnett has received honoraria from Medtronic, and Boston Scientific; and has served as a consultant for Medtronic and Abbott. Dr Nair has received a grant-in-aid from Biosense Webster and Medtronic Inc, CIHR, and Heart and Stroke Foundation of Canada; and has received honoraria and consulting fees from Medtronic, Biosense Webster, and Boston Scientific. Dr Curila has served as a consultant for, and has received honoraria from, Medtronic, Biotronik, and Abbott. Dr Ellenbogen has served as a consultant for Medtronic, Boston Scientific, Abbott, and Biotronik; and has received honoraria from Medtronic, Boston Scientific, and Biotronik. Dr Vijayaraman has received honoraria and research and fellowship support from, and has served as a consultant for, Medtronic; has served as a consultant for Abbott and Eaglepoint LLC; has received honoraria from Boston Scientific and Biotronik; and holds a patent for HBP delivery tool. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: His-Purkinje conduction system pacing (HPCSP) using His bundle pacing (HBP) or left bundle branch pacing (LBBP) has emerged as an alternative to biventricular pacing (BVP) in patients requiring cardiac resynchronization therapy (CRT)., Objectives: The aim of the study was to compare the feasibility and clinical efficacy of HOT-CRT (His-Purkinje conduction system pacing Optimized Trial of Cardiac Resynchronization Therapy) with BVP in patients with heart failure, reduced ejection fraction, and indication for CRT., Methods: This was a prospective, randomized, controlled trial of HOT-CRT and BVP in patients with LVEF <50% and indications for CRT. If HPCSP resulted in incomplete electrical resynchronization, a coronary sinus (CS) lead was added. The primary outcome was the change in left ventricular ejection fraction (LVEF) at 6 months. The primary safety endpoint was freedom from major complications., Results: A total of 100 patients (female 31%, aged 70 ± 12 years, LVEF 31.5% ± 9.0%) were randomized. HOT-CRT was successful in 48 of 50 (96%) and BVP-CRT in 41 of 50 (82%) patients (P = 0.03). QRS duration significantly decreased from 164 ± 26 ms to 137 ± 20 ms with HOT-CRT and 166 ± 28 ms to 141 ± 19 ms with BVP. Fluoroscopy results (18.8 ± 12.4 min vs 23.8 ± 12.4 min, P = 0.05) and procedure duration (119 ± 42 min vs 114 ± 36 min, P = 0.5) were similar. The primary outcome of change in LVEF at 6 months was greater in HOT-CRT than in BVP (12.4% ± 7.3% vs 8.0% ± 10.1%, P = 0.02). The primary safety endpoint was similar (98% vs 94%, P = 0.62). Echocardiographic response of improvement in LVEF >5% occurred in 80% vs 61% (P = 0.06). Complications occurred in 3 (6%) in HOT-CRT vs 10 (20%) in BVP (P = 0.03)., Conclusions: HPCSP-guided CRT resulted in greater change in LVEF compared with BVP. Randomized clinical trials with long-term follow-up are necessary. (His-Purkinje Conduction System Pacing Optimized Trial of Cardiac Resynchronization Therapy [HOT-CRT]; NCT04561778)., Competing Interests: Funding Support and Author Disclosures This work was funded by a Geisinger Foundation internal grant. Dr Vijayaraman has been a consultant for, and the recipient of honoraria, research support, and fellowship support from Medtronic; a consultant for Abbott; the recipient of honoraria from Biotronik and Boston Scientific; and the holder of a patent on the HBP delivery tool. Dr Subzposh has been the recipient of honoraria from Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Lumenless leads (LLLs) are widely used for left bundle branch area pacing (LBBAP). Recently, stylet-driven leads (SDLs) have also been used for LBBAP., Objective: The purpose of this study was to evaluate the acute performance of SDLs during LBBAP in comparison with LLLs., Methods: Consecutive patients undergoing LBBAP for bradycardia or cardiac resynchronization therapy indications at 2 high-volume, early conduction system pacing adopters, tertiary centers were included from January 2019 to July 2023. Patients received either SDLs or LLLs at the discretion of the implanting physician. Acute performance and follow-up data of both lead types were evaluated., Results: A total of 925 LBBAP implants were included, 655 using LLLs and 270 using SDLs. Overall, LBBAP acute success was significantly higher with LLLs than SDLs (95.3% vs 85.1%, respectively; P <.001) even after the learning curve (97% vs 86%; P = .013). LLLs were implanted in more mid-basal septal positions in comparison with SDLs, which tended to be implanted in more inferior and mid-apical septal positions. Acute lead-related complications were higher with SDLs than LLLs (15.9% vs 6.1%, respectively; P <.001) with 15 cases of lead damage during implant (4.4% vs 0.5%; P <.001) but decreased with acquired experience and were comparable in the last 100 patients included in each group. Lead implant and fluoroscopy times were shorter for SDLs, with lead dislodgment occurring in 0.9% with LLLs and 1.5% with SDLs ( P = .489)., Conclusion: Acute lead performance proved to be different between LLLs and SDLs. A specific learning curve should be considered for SDLs even for implanters with extensive previous experience with LLLs., (© 2023 Heart Rhythm Society. Published by Elsevier Inc.)

Background: Cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) is a well established therapy in patients with reduced left ventricular ejection fraction (LVEF), heart failure, and wide QRS or expected frequent ventricular pacing. Left bundle branch area pacing (LBBAP) has recently been shown to be a safe alternative to BVP., Objectives: The aim of this study was to compare the clinical outcomes between BVP and LBBAP among patients undergoing CRT., Methods: This observational study included patients with LVEF ≤35% who underwent BVP or LBBAP for the first time for Class I or II indications for CRT from January 2018 to June 2022 at 15 international centers. The primary outcome was the composite endpoint of time to death or heart failure hospitalization (HFH). Secondary outcomes included endpoints of death, HFH, and echocardiographic changes., Results: A total of 1,778 patients met inclusion criteria: 981 BVP, 797 LBBAP. The mean age was 69 ± 12 years, 32% were female, 48% had coronary artery disease, and mean LVEF was 27% ± 6%. Paced QRS duration in LBBAP was significantly narrower than baseline (128 ± 19 ms vs 161 ± 28 ms; P < 0.001) and significantly narrower compared to BVP (144 ± 23 ms; P < 0.001). Following CRT, LVEF improved from 27% ± 6% to 41% ± 13% (P < 0.001) with LBBAP compared with an increase from 27% ± 7% to 37% ± 12% (P < 0.001) with BVP, with significantly greater change from baseline with LBBAP (13% ± 12% vs 10% ± 12%; P < 0.001). On multivariable regression analysis, the primary outcome was significantly reduced with LBBAP compared with BVP (20.8% vs 28%; HR: 1.495; 95% CI: 1.213-1.842; P < 0.001)., Conclusions: LBBAP improved clinical outcomes compared with BVP in patients with CRT indications and may be a reasonable alternative to BVP., Competing Interests: Funding Support and Author Disclosures Dr Vijayaraman has received honoraria and consultancy, research, and fellowship support from Medtronic; has served as a consultant for Abbott and Eaglepoint; has received honoraria from Boston Scientific and Biotronik; and has a patent for a His bundle pacing delivery tool. Dr Sharma has received honoraria from Medtronic; and has served as a consultant for Medtronic, Abbott, and Biotronik. Dr Cano has received honoraria from and served as a consultant for Medtronic, Biotronik, and Boston Scientific. Dr Ponnusamy has received honoraria from Medtronic. Dr Herweg has served as a speaker and consultant for Abbott; and has received speaking and fellowship support from Medtronic. Dr Jastrzebski has received honoraria from and served as a consultant for Medtronic and Abbott. Dr Zou has received honoraria from Abbott, Biotronik, Boston Scientific, Medtronic, and Microport. Dr Chelu has received research support from Patient-Centered Outcomes Research Institute, National Institutes of Health, Abbott, and Impulse Dynamics; and has received honorarium from Impulse Dynamics. Dr Vernooy has served as a consultant for Biosense Webster, Philips, Medtronic, Abbott, and Boston Scientific; and has received research and educational grants to his institution from Philips, Abbott, Medtronic, and Biosense Webster. Dr Whinnett has received honoraria from Medtronic and Boston Scientific; and has served as a consultant for Medtronic and Abbott. Dr Nair has received grants-in-aid from Biosense Webster, Medtronic, Canadian Institutes of Health Research, and Heart and Stroke Foundation of Canada; and has received honoraria and consulting fees from Medtronic, Biosense Webster, and Boston Scientific. Dr Curila has served as a consultant for and received honoraria from Medtronic, Biotronik, and Abbott. Dr Ellenbogen has served as a consultant for Medtronic, Boston Scientific, Abbott, and Biotronik; and has received honoraria from Medtronic, Boston Scientific, and Biotronik. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Disclosures Drs Bernabei and Subzposh have received honorarium from Medtronic. Dr Zimmerman, R. Rose, and Dr Butler are employees and shareholders of Medtronic. Dr Ellenbogen has received research support from Boston Scientific, Biosense Webster, Medtronic, St. Jude Medical, and the National Institutes of Health. Dr Ellenbogen is a consultant for Boston Scientific, St. Jude Medical, Atricure, and Medtronic. Dr Ellenbogen has received honoraria from Boston Scientific, Biotronik, Biosense Webster, Atricure, and Medtronic. The other authors report no conflicts.

An 88-year-old woman underwent atrioventricular node ablation and left bundle branch pacing for atrial fibrillation. She presented to the emergency room several hours after discharge with dyspnea. An echocardiogram revealed a giant interventricular septal hematoma. The patient was successfully treated with conservative medical therapy, with eventual complete resolution of the hematoma. ( Level of Difficulty: Intermediate. )., Competing Interests: Dr. Vijayaraman has been a consultant for Abbott, Biotronik and Eaglepoint LLC; holder of a patent for HBP delivery tool and the recipient of honoraria and research and fellowship support from Medtronic; a consultant for Abbott and Biotronik; and the holder of a patent HBP delivery tool for Eaglepoint LLC. All other have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2023 The Authors.)

Left bundle branch area pacing has emerged as a safe and feasible alternative to conventional pacing. Acute septal injury, septal perforation, and arteriovenous fistula are potential risks of deep septal implants. Contrast drainage through the lesser cardiac veins and subsequent filling of major epicardial vessels may be benign observations noted during forceful hand injection. ( Level of Difficulty: Advanced. )., Competing Interests: Dr Batul has received honorarium from Medtronic. Dr Subzposh has received honorarium from Medtronic. Dr Vijayaraman has received fellowship support from Medtronic; has served as a speaker and researcher for Medtronic; has served as a consultant for Medtronic, Biotronik, and Abbott; and has received honorarium from Boston Scientific. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2022 The Authors.)

Background: Cardiac resynchronization therapy (CRT) using biventricular pacing (BVP) is effective in patients with heart failure, left bundle branch block (LBBB), and reduced left ventricular function. Left bundle branch area pacing (LBBAP) has been reported as an alternative option for CRT., Objective: The purpose of this study was to assess the feasibility and outcomes of LBBAP in patients who failed conventional BVP because of coronary venous (CV) lead complications or who were nonresponders to BVP., Methods: At 16 international centers, LBBAP was attempted in patients with conventional CRT indication who failed BVP because of CV lead complications or lack of therapeutic response to BVP. Heart failure hospitalization (HFH) and death, echocardiographic outcomes, procedural data, pacing parameters, and lead complications including CV lead failure are reported., Results: LBBAP was successfully performed in 200 patients (CV lead failures 156; nonresponders 44) (age 68 ± 11 years; female 35%; LBBB 55%; right ventricular pacing 23%; ischemic cardiomyopathy 28%; nonischemic cardiomyopathy 63%; left ventricular ejection fraction [LVEF] ≤35% in 80%). Procedural duration was 119.5 ± 59.6 minutes, and fluoroscopy duration was 25.7 ± 18.5 minutes. LBBAP threshold and R-wave amplitudes were 0.68 ± 0.35 V @ 0.45 ms and 10.4 ± 5 mV at implant, respectively, and remained stable during mean follow-up of 12 ± 10.1 months. LBBAP resulted in significant QRS narrowing from 170 ± 28 ms to 139 ± 25 ms (P <.001) with V 6 R-wave peak times of 85 ± 17 ms. LVEF improved from 29% ± 10% at baseline to 40% ± 12% (P <.001) during follow-up. The risk of death or HFH was lower in those with CV lead failure than in nonresponders (hazard ratio 0.357; 95% confidence interval 0.168-0.756; P = .007) CONCLUSION: LBBAP is a viable alternative to CRT in patients who failed conventional BVP due to CV lead failure or who were nonresponders., (Copyright © 2022 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) is well-established therapy in patients with reduced left ventricular ejection fraction (LVEF) and bundle branch block or indication for pacing. Conduction system pacing (CSP) using His-bundle pacing (HBP) or left bundle branch area pacing (LBBAP) has been shown to be a safe and more physiological alternative to BVP., Objective: The purpose of this study was to compare the clinical outcomes between CSP and BVP among patients undergoing CRT., Methods: This observational study included consecutive patients with LVEF ≤35% and class I or II indications for CRT who underwent successful BVP or CSP at 2 major health care systems. The primary outcome was the composite endpoint of time to death or heart failure hospitalization (HFH). Secondary outcomes included subgroup analysis in left bundle branch block as well as individual endpoints of death and HFH., Results: A total of 477 patients (32% female) met inclusion criteria (BVP 219; CSP 258 [HBP 87, LBBAP 171]). Mean age was 72 ± 12 years, and mean LVEF was 26% ± 6%. Comorbidities included hypertension 70%, diabetes mellitus 45%, and coronary artery disease 52%. Paced QRS duration in CSP was significantly narrower than BVP (133 ± 21 ms vs 153 ± 24 ms; P <.001). LVEF improved in both groups during mean follow-up of 27 ± 12 months and was greater after CSP compared to BVP (39.7% ± 13% vs 33.1% ± 12%; P <.001). Primary outcome of death or HFH was significantly lower with CSP vs BVP (28.3% vs 38.4%; hazard ratio 1.52; 95% confidence interval 1.082-2.087; P = .013)., Conclusion: CSP improved clinical outcomes compared to BVP in this large cohort of patients with indications for CRT., (Copyright © 2022 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Introduction: His bundle pacing (HBP) is the most physiologic form of pacing and has been associated with reduced risk for heart failure hospitalization (HFH) and mortality compared to right ventricular pacing. Left bundle branch area pacing (LBBAP) is a safe and effective alternative option for patients needing ventricular pacing. The aim of this study was to compare the clinical outcomes between LBBAP and HBP among a large cohort of patients undergoing permanent pacemaker implantation., Methods: This observational registry included consecutive patients with AV block/AV node ablation who underwent de novo permanent pacemaker implantations with successful LBBAP or HBP between April 2018 and October 2020. The primary outcome was the composite endpoint of time to death from any cause or HFH. Secondary outcomes included the composite endpoint among patients with prespecified ventricular pacing burden and individual outcomes., Results: The study population included 359 patients who met the inclusion criteria (163 in the HBP and 196 in the LBBAP group). Paced QRSd during LBBAP was similar to HBP (125 ± 20.2 vs. 126 ± 23.5 ms, p = .643). There were no statistically significant differences in the primary composite outcome in LBBAP (17.3%) compared to HBP (24.5%) (hazard ratio [HR]: 1.15, 95% CI: 0.72-1.82, p = .552). Secondary outcomes of death (10% vs. 17%; HR: 1.3, 95% CI: 0.73-2.33, p = .38) and HFH (10% vs. 12%; HR: 1.02, 95% CI: 0.54-1.94, p = .94) were not different among both groups., Conclusions: There were no statistically significant differences in the clinical outcomes of death or HFH in LBBAP when compared to HBP., (© 2022 Wiley Periodicals LLC.)

Background: Cardiac resynchronization therapy (CRT) using biventricular pacing has limited efficacy in patients with heart failure (HF) and right bundle branch block (RBBB). Left bundle branch area pacing (LBBAP) is a novel physiologic pacing option., Objective: The aim of the study was to assess the feasibility and outcomes of LBBAP in HF patients with RBBB and reduced left ventricular systolic function, and indication for CRT or ventricular pacing., Methods: LBBAP was attempted in patients with left ventricular ejection fraction (LVEF) <50%, RBBB, HF, and indications for CRT or ventricular pacing. Procedural, pacing, and electrocardiographic parameters; clinical response (no HF hospitalization and improvement in NYHA class); and echocardiographic response (≥5% increase in ejection fraction) to LBBAP were assessed., Results: LBBAP was attempted in 121 patients and successful in 107 (88%). Patient characteristics included age 74 ± 12 years, female 25%, ischemic cardiomyopathy 49%, and ejection fraction 35% ± 9%. QRS axis at baseline was normal in 24%, left axis 63%, right axis 13%. LBBAP threshold and R-wave amplitudes were 0.8 ± 0.3 V @ 0.5 ms and 10 ± 9 mV at implant and remained stable during mean follow-up of 13 ± 8 months. LBBAP resulted in narrowing of QRS duration (156 ± 20 ms to 150 ± 24 ms ( P = .01) with R-wave peak times in V 6 of 85 ± 16 ms. LVEF improved from 35% ± 9% to 43% ± 12% ( P < .01). Clinical and echocardiographic response was observed in 60% and 61% of patients, respectively. Female sex and reduction in QRS duration with LBBAP were predictive of echocardiographic response and super-response., Conclusion: LBBAP is a feasible alternative to deliver CRT or physiologic ventricular pacing in patients with RBBB, HF, and LV dysfunction., (© 2022 Heart Rhythm Society. Published by Elsevier Inc.)

Background: Atrioventricular node ablation (AVNA) with right ventricular or biventricular pacing (conventional pacing; CP) is an effective therapy for patients with refractory atrial fibrillation (AF). Conduction system pacing (CSP) using His bundle pacing or left bundle branch area pacing preserves ventricular synchrony., Objective: The aim of our study is to compare the clinical outcomes between CP and CSP in patients undergoing AVNA., Methods: Patients undergoing AVNA at Geisinger Health System between January 2015 and October 2020 were included in this retrospective observational study. CP or CSP was performed at the operators' discretion. Procedural, pacing parameters, and echocardiographic data were assessed. Primary outcome was the combined endpoint of time to death or heart failure hospitalization (HFH) and was analyzed using Cox proportional hazards. Secondary outcomes were individual outcomes of time to death and HFH., Results: AVNA was performed in 223 patients (CSP, 110; CP, 113). Age was 75 ± 10 years, male 52%, hypertension 67%, diabetes 25%, coronary disease 40%, and left ventricular ejection fraction (LVEF) 43% ± 15%. QRS duration increased from 103 ± 30 ms to 124 ± 20 ms ( P < .01) in CSP and 119 ± 32 ms to 162 ± 24 ms in CP ( P < .001). During a mean follow-up of 27 ± 19 months, LVEF significantly increased from 46.5% ± 14.2% to 51.9% ± 11.2% ( P = .02) in CSP and 36.4% ± 16.1% to 39.5% ± 16% ( P = .04) in CP. The primary combined endpoint of time to death or HFH was significantly reduced in CSP compared to CP (48% vs 62%; hazard ratio 0.61, 95% confidence interval 0.42-0.89, P  < .01). There was no reduction in the individual secondary outcomes of time to death and HFH in the CSP group compared to CP., Conclusion: CSP is a safe and effective option for pacing in patients with AF undergoing AVNA in high-volume centers., (© 2022 Heart Rhythm Society. Published by Elsevier Inc.)

Objectives: This study aims to assess the safety and feasibility of achieving His-Purkinje conduction system pacing (HPCSP) in consecutive patients with atrioventricular block (AVB) and to describe the site of conduction block in patients with infranodal AVB., Background: HPCSP has evolved as the preferred form of physiologic pacing. Left bundle branch area pacing (LBBAP) has emerged as an effective alternative to His bundle pacing (HBP)., Methods: Consecutive patients with AVB referred for pacemaker implantation were included in the study. HBP or LBBAP was attempted in all patients. Site of conduction block was identified as nodal or infranodal (intra-Hisian or infra-Hisian) AVB., Results: HPCSP was attempted in 333 consecutive patients with AVB and was successful in 322 (97%) patients. HBP was achieved in 140 patients, LBBAP in 179 patients, and both in 3 patients. Site of conduction block was nodal in 55% and infranodal in 45% (intra-Hisian 89%; infra-Hisian 4%; indeterminate 7%). QRS duration at baseline was 111 ± 27 versus 129 ± 31 (P < 0.001) compared to 126 ± 24 vs 125 ± 21 milliseconds (P = 0.75) during HBP and LBBAP, respectively. HBP thresholds at implant were higher compared to LBBAP (1.2 ± 0.7 V at 0.9 milliseconds vs 0.6 ± 0.3 V at 0.5 milliseconds; P < 0.001) but remained stable during follow-up. Lead revision was required in 3% and 2% of patients with HBP and LBBAP, respectively., Conclusions: HPCSP pacing was successfully performed in 97% of unselected patients with AVB irrespective of the site of conduction block. True infra-Hisian block (distal His-Purkinje conduction disease) is rare. HBP and LBBAP were complementary in achieving stable and low capture thresholds., Competing Interests: Funding Support and Author Disclosures Dr Vijayaraman has received personal fees from Medtronic, Biotronik, and Abbott-Advisory; and has a patent for an HBP delivery tool. Dr Subzposh has received personal fees from Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Left bundle branch area pacing (LBBAP) has been shown to be a feasible option for patients requiring ventricular pacing., Objective: The purpose of this study was to compare clinical outcomes between LBBAP and RVP among patients undergoing pacemaker implantation METHODS: This observational registry included patients who underwent pacemaker implantations with LBBAP or RVP for bradycardia indications between April 2018 and October 2020. The primary composite outcome included all-cause mortality, heart failure hospitalization (HFH), or upgrade to biventricular pacing. Secondary outcomes included the composite endpoint among patients with a prespecified burden of ventricular pacing and individual outcomes., Results: A total of 703 patients met inclusion criteria (321 LBBAP and 382 RVP). QRS duration during LBBAP was similar to baseline (121 ± 23 ms vs 117 ± 30 ms; P = .302) and was narrower compared to RVP (121 ± 23 ms vs 156 ± 27 ms; P <.001). The primary composite outcome was significantly lower with LBBAP (10.0%) compared to RVP (23.3%) (hazard ratio [HR] 0.46; 95%T confidence interval [CI] 0.306-0.695; P <.001). Among patients with ventricular pacing burden >20%, LBBAP was associated with significant reduction in the primary outcome compared to RVP (8.4% vs 26.1%; HR 0.32; 95% CI 0.187-0.540; P <.001). LBBAP was also associated with significant reduction in mortality (7.8% vs 15%; HR 0.59; P = .03) and HFH (3.7% vs 10.5%; HR 0.38; P = .004)., Conclusion: LBBAP resulted in improved clinical outcomes compared to RVP. Higher burden of ventricular pacing (>20%) was the primary driver of these outcome differences., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: His bundle pacing (HBP) is the most physiologic form of pacing. Long-term HBP capture threshold stability and its relation to lead characteristics at the time of implantation have not been adequately described. The aim of this study was to characterize HB capture threshold in follow-up and to identify potential lead characteristics predictive of lead capture instability., Methods and Results: Consecutive patients with successful HBP for bradycardia indications were identified from the Geisinger HBP registry. His bundle capture thresholds, baseline comorbidities, and radiographic lead slack characteristics were analysed. An increase in HB capture threshold ≥1 V above implant values at any time during follow-up was tracked. Forty-four of the 294 studied (15%) experienced HB capture threshold increase by ≥ 1 V. Threshold increase was seen early (41% by 8 weeks, 66% by 1 year). Eighteen (6%) patients required lead revision in follow-up. Abnormal slack shape was associated with a trend toward capture threshold increase [hazard ratio (HR) 2.07; 95% confidence interval (CI) 0.9-4.6; P = 0.08]. Non-perpendicular angle of lead insertion on radiography was associated with the capture threshold increase (HR 2.81, 95% CI 1.4-5.8; P < 0.01)., Conclusion: His bundle capture threshold remains stable in the majority (85%) of patients. Implant characteristics may predict the threshold rise. Further evaluation of the aetiology of threshold increase and design changes in lead and delivery systems may lead to chronically stable capture thresholds., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2020. For permissions, please email: journals.permissions@oup.com.)

Left bundle branch pacing (LBBP) has emerged as an alternative to His bundle pacing (HBP) to achieve physiologic ventricular stimulation. The extent of myocardial injury during permanent LBBP implantation is currently not known. The aim of the study was to prospectively assess the extent of myocardial injury during LBBP implantation. Cardiac troponin (cTn) levels were measured at baseline and 6-12 h following permanent LBBP. The number of attempts to achieve LBBP was documented. Troponin levels were measured in a control population undergoing other electrophysiology procedures including HBP, other devices involving right ventricular (RV) pacing, radiofrequency ablation for atrial fibrillation (AF) and supraventricular tachycardia (SVT). Significant elevation of troponin (SET) was defined as threefold increase above the upper reference limit (URL) for cTn. Between December 2019 and April 2020, 204 were prospectively enrolled: LBBP in 98 and Control group 106 (SVT, 55; AF, 20; HBP, 17; other devices, 14). SET (>3× URL) was seen in 49.4% of patients in the LBBP group compared to 58.4% in the control group (p = .23). Peak troponin levels were greater in the control group compared to the LBBP group (230.3 ± 320.1 vs. 87.4 ± 71.3 pg/ml; p = .0001). Compared to LBBP (49.4%), SET was observed less frequently following HBP (17.5%; p = .01), and other device implantation (29%; p = .15). Patients requiring >2 attempts (n = 33) had significantly higher incidence of SET compared to <2 attempts (n = 56; 66.7% vs. 39.3%; p = .01). LBBP implantation is associated with myocardial injury. Asymptomatic troponin release following LBBP is less than or comparable to other interventional electrophysiology procedures., (© 2021 Wiley Periodicals LLC.)

Objectives: This study sought to evaluate the correlation between His bundle (HB) pacing (HBP) implantation characteristics, lead-tip location, and association of intraprocedural His recordings with approximated HB anatomic landmarks using computed tomography (CT) imaging., Background: HBP continues to grow in clinical practice due to offering true physiological pacing. However, a clear understanding of HB anatomy and the lead-tip location's influence on pacing characteristics is lacking., Methods: The IMAGE-HBP study (Imaging Study of Lead Implant for His Bundle Pacing) was a prospective, multicenter study designed to assess implantation characteristics of the SelectSecure Model 3830 lead placed at the HB, evaluate protocol-specified HBP success (His recording present on electrogram and HBP threshold ≤2.5 V at 1 ms), and correlation between lead-tip location by CT imaging and HBP characteristics as well as lead-related complications through 12 months., Results: Sixty-nine patients underwent a lead implantation attempt at the HB. Of these, 61 patients (88%) had a lead successfully implanted at the HB, and 52 patients (75%) met the pre-specified definition of successful HBP. In 51 patients with CT imaging, 11 leads (22%) were placed in the atrial aspect of the HB region (36% selective HBP), and 40 leads (78%) were placed in the ventricular aspect (28% selective HBP). Four of the 51 patients had P-wave oversensing, all with leads in the atrium. Freedom from lead-related complication at 12 months was 93%., Conclusions: Successful HBP could be achieved at lead-tip locations in the atrium or ventricle but is preferable in the ventricle to eliminate risk of oversensing. The IMAGE-HBP study offers better insight into approximated HB anatomic landmarks, lead-tip location, and correlation with pacing characteristics. (Imaging Study of Lead Implant for His Bundle Pacing [IMAGE-HBP]; NCT03294317)., Competing Interests: Author Disclosures The IMAGE-HBP study (NCT03294317) was funded by Medtronic, Inc. Dr. Vijayaraman had been a consultant and has received honoraria from Abbott, Biotronik, Boston Scientific, Medtronic, Eaglepoint LLC, and Biosense Webster; has received research funding and fellowship support from Medtronic; and has a patent pending for HBP delivery tool. Dr. Dandamudi has received speaking and consulting honoraria and research funding from Medtronic. Dr. Subzposh has received honoraria and funding from Medtronic. Dr. Padala has served as a consultant for Medtronic. Dr. Ellenbogen has served as a consultant and has received honoraria from Abbott, Biotronik, Boston Scientific, Medtronic, and Biosense Webster. Dr. Bergemann is an employee and shareholder of Medtronic, Inc. Ms. Hughes is an employee and shareholder of Medtronic, Inc. Ms. Harris is an employee and shareholder of Medtronic, Inc. Dr. Fagan is an employee and shareholder of Medtronic, Inc. Dr. Yang is an employee and shareholder of Medtronic, Inc. Dr. Koneru has received teaching honoraria from Medtronic, Abbott Medical, and Biotronik; and fellowship support from Biosense Webster, Abbott Medical, Boston Scientific, and Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: His bundle pacing (HBP) is the most physiologic form of pacing but associated with higher thresholds and lower success in patients with His-Purkinje conduction disease. Recent reports have described transvenous left bundle branch area pacing (LBBAP)., Objective: We aimed to prospectively evaluate the feasibility and the electrophysiologic and echocardiographic characteristics of LBBAP., Methods: Patients requiring pacing for bradycardia or heart failure indications (failed left ventricular [LV] lead) were prospectively enrolled. LBBAP was performed with a Medtronic 3830 lead. Presence of left bundle branch (LBB) potential, paced QRS morphology/duration, and peak LV activation time (pLVAT) were recorded at implant. Pacing threshold and sensing was assessed at implant and follow-up. Echocardiography was performed to assess the approximate lead location and impact on tricuspid valve function., Results: LBBAP was successful in 93 of 100 (93%) patients. Mean age was 75 ± 13 years; men 69%, left bundle branch block 24%, right bundle branch block 25%, intraventricular conduction defect 8%. Indications for pacing were atrioventricular (AV) block 54%, sinus node dysfunction 23%, AV node ablation 7%, cardiac resynchronization therapy 11%, HBP lead failure 7%. Baseline QRS duration was 133 ± 35 ms. Paced QRS duration was 136 ± 17 ms. LBB potentials were observed in 63 patients with left bundle branch - ventricle (LBB-V) interval of 27 ± 6 ms. pLVAT was 75 ± 16 ms. Pacing threshold at implant was 0.6 ± 0.4 V @ 0.5 ms and R waves were 10 ± 6 mV and remained stable at median follow-up of 3 months. The lead depth in the septum was approximately 1.4 ± 0.23 cm., Conclusions: LBBAP was feasible in a high percentage of patients with low thresholds during acute follow-up. HBP and LBBAP may significantly increase the overall success of physiologic pacing., (Copyright © 2019 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: The His-SYNC pilot trial was the first randomized comparison between His bundle pacing in lieu of a left ventricular lead for cardiac resynchronization therapy (His-CRT) and biventricular pacing (BiV-CRT), but was limited by high rates of crossover., Objective: To evaluate the results of the His-SYNC pilot trial utilizing treatment-received (TR) and per-protocol (PP) analyses., Methods: The His-SYNC pilot was a multicenter, prospective, single-blinded, randomized, controlled trial comparing His-CRT vs BiV-CRT in patients meeting standard indications for CRT (eg, NYHA II-IV patients with QRS >120 ms). Crossovers were required based on prespecified criteria. The primary endpoints analyzed included improvement in QRS duration, left ventricular ejection fraction (LVEF), and freedom from cardiovascular (CV) hospitalization and mortality., Results: Among 41 patients enrolled (aged 64 ± 13 years, 38% female, LVEF 28%, QRS 168 ± 18 ms), 21 were randomized to His-CRT and 20 to BiV-CRT. Crossover occurred in 48% of His-CRT and 26% of BiV-CRT. The most common reason for crossover from His-CRT was inability to correct QRS owing to nonspecific intraventricular conduction delay (n = 5). Patients treated with His-CRT demonstrated greater QRS narrowing compared to BiV (125 ± 22 ms vs 164 ± 25 ms [TR], P < .001;124 ± 19 ms vs 162 ± 24 ms [PP], P < .001). A trend toward higher echocardiographic response was also observed (80 vs 57% [TR], P = .14; 91% vs 54% [PP], P = .078). No significant differences in CV hospitalization or mortality were observed., Conclusions: Patients receiving His-CRT on-treatment demonstrated superior electrical resynchronization and a trend toward higher echocardiographic response than BiV-CRT. Larger prospective studies may be justifiable with refinements in patient selection and implantation techniques to minimize crossovers., (Copyright © 2019 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Introduction: Several single-center short-term studies have demonstrated the feasibility, safety, and positive clinical outcomes of permanent His bundle pacing (HBP). We performed a retrospective study to evaluate long-term technical and safety performances of HBP in a large population of pacemaker patients from two different centers., Methods and Results: The analysis includes 844 patients (345 female, mean age = 75 ± 9 years) who underwent successful permanent HBP for pacemaker indications from 2004 to 2016. The main endpoints were long term electrical performances including pacing threshold, sensing, impedance, and freedom from pacing related complications. The pacing indication was AV Block in 348 (41.2%) patients, sinus node disease in 147 (17.4%), any bradycardia indication in patients with atrial fibrillation in 335 (39.7%) patients and need for cardiac resynchronization therapy in 14 (1.7%) patients. Mean pacing capture thresholds and sensed R waves were 1.6 V and 5.8 mV, respectively at implant and 2.0 V and 6.1 mV at chronic follow-up. During the median follow up of 3 years (interquartile range = 1-6 years), HBP was free of any complication in 91.6% of patients. In the first 368 patients, HBP was achieved using a deflectable curve delivery system, while in 476 using the fixed curve sheath. A significant difference was found in the thresholds (2.4 ± 1.0 V and 1.7 ± 1.1 V, P < .001, respectively) and complications (11.9% and 4.2%, P < .001, respectively) between the two groups., Conclusions: Permanent HBP was safe and effective during long-term follow-up. The fixed curved delivery sheath offered significantly better electrical parameters and reliability over time. The results of this multicenter study are consistent with recent studies., (© 2019 Wiley Periodicals, Inc.)

Background: Permanent His bundle pacing (HBP) is a physiological alternative to right ventricular pacing. However, concerns remain about the feasibility and safety of lead extraction from the His bundle region., Objective: The aim of our study was to assess the safety and feasibility of extraction of chronically implanted permanent HBP leads in addition to report on the feasibility of reimplanting in the His bundle region., Methods: Patients undergoing extraction of leads from the His bundle location for standard indications were studied. The primary outcomes were removal success rates, need for extraction tools, and feasibility of reimplantation in the His bundle region., Results: Thirty patients (male 23 (27%); mean age 73.3 ± 14 years) with permanent HBP leads of at least 6-month duration were included. The indications for removal of the HBP leads were infection (n = 3), lead failure (n = 22), nonfunctional lead (n = 3), and upgrade to implantable cardioverter-defibrillator (n = 2). The mean duration of the implanted leads was 25 ± 18 months (range 6-72 months). Removal of HBP leads was successful in 8 of 8 patients (100%) with ≤12-month duration and 21 of 22 patients (95%) with >12-month duration. Extraction tools were used in 4 patients, while manual traction was successful in the remaining patients. Reimplantation in the His-Purkinje conduction system was successful in 19 of 22 patients (86%)., Conclusion: In this largest study of HBP lead extractions, the overall success rate of extraction of chronically implanted HBP leads was high with a low complication rate. The need for mechanical extraction tools was low, and reimplantation in the His-Purkinje conduction system was feasible., (Copyright © 2019 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Purpose of Review: Cardiac resynchronization therapy (CRT) using biventricular pacing (BVP) is the cornerstone of treatment for patients with heart failure and left bundle branch block. Up to a third of patients do not respond to BVP. This article reviews the utility of His-bundle pacing (HBP) and Left ventricular (LV) endocardial pacing as alternatives to BVP to provide ventricular synchrony., Recent Findings: HBP has shown promising results in observational studies. By significantly narrowing or normalizing QRS, HBP has improved clinical outcomes including ejection fractions both as a rescue option in patients who failed BVP or as a primary alternative. LV endocardial pacing has also shown promise with improved clinical outcomes. Using traditional pacing leads or novel technology, direct stimulation of the LV endocardium allows for better site selection as well as a more physiological activation of the LV compared to traditional epicardial LV stimulation. HBP and LV endocardial pacing are valuable alternatives to traditional BVP to achieve CRT. Randomized clinical trials in progress will allow for a deeper understanding of how they can benefit our patients.

Right ventricular pacing is associated with pacing-induced cardiomyopathy in some patients. His Bundle Pacing (HBP) is an alternative site to pace to achieve ventricular contraction with fewer adverse hemodynamic effects. HBP has been shown to be safe and feasible in the short term. The few studies that look at long-term results of HBP are promising with regard to electrophysiological, echocardiographic, and clinical outcomes. Further randomized clinical trials are needed to fully understand the long-term effects of HBP., (Copyright © 2018 Elsevier Inc. All rights reserved.)

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., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Right ventricular pacing (RVP) is associated with heart failure and increased mortality. His-bundle pacing (HBP) is a physiological alternative to RVP., Objective: The purpose of this study was to report long-term performance and compare the clinical outcomes of permanent HBP vs RVP., Methods: All patients requiring pacemaker implantation underwent an attempt at permanent HBP in 2011 at one hospital and RVP at the sister hospital. Patients were followed from implantation, 2 weeks, 2 months, and yearly for 5 years. Left ventricular ejection fraction (LVEF), pacing thresholds, lead revision, and generator change were tracked. Primary outcome was the combined endpoint of death or heart failure hospitalization (HFH) at 5 years., Results: HBP was attempted in 94 consecutive patients and was successful in 75 (80%); 98 patients underwent RVP. LVEF remained unchanged in the HBP group (55% ± 8% vs 57% ± 6%; P = .13), whereas significant decline was noted in the RVP group (57% ± 7% vs 52% ± 11%; P = .002). Incidence of pacing-induced cardiomyopathy was significantly lower in HBP compared to RVP patients (2% vs 22%; P = .04). At 5 years, death or HFH was significantly lower in HBP compared to RVP patients with >40% ventricular pacing (32% vs 53%; hazard ratio 1.9; P = .04). At 5 years, the need for lead revisions (6.7% vs 3%) and for generator change (9% vs 1%) were higher in the HBP group., Conclusion: In patients undergoing pacemaker implantation, permanent HBP was associated with reduction in death or HFH during long-term follow-up compared to RVP. HBP was associated with higher rates of lead revisions and generator change., (Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: Atrioventricular node ablation (AVNA) and right ventricular pacing (RVP) are effective therapies for patients with atrial fibrillation (AF) and rapid ventricular rates. His bundle pacing (HBP) is a physiologic alternative to RVP. The aim of our study is to assess the feasibility and safety of HBP in patients undergoing AVNA and its effect on left ventricular (LV) function., Methods and Results: Permanent HBP is the preferred form of ventricular pacing at our institute. Atrioventricular node ablation and HBP were performed in patients with AF and difficulty in rate control. His bundle pacing implant characteristics and thresholds were recorded. Fluoroscopic relationship of AVNA site to HBP lead electrodes was documented. Left ventricular ejection fraction (LVEF) and New York Heart Association (NYHA) functional class at baseline and during follow-up were assessed. Forty-two patients underwent HBP and AVNA: age 74 ± 11 years; men 45%; HTN 64%; DM 19%; CAD 36%; permanent AF 40%; cardiomyopathy 55%. His bundle pacing was successful in 40 of 42 patients (95%). Successful AVNA site was at or below the ring electrode in 22 (no acute change in HBP threshold); above the ring electrode in 13 and left side in 2 pts (acute increase in HBP threshold in 7 of 15 pts). Final HBP threshold at implant was 1 ± 0.8 V@1 ms and increased to 1.6 ± 1.2 V@1 ms during a mean follow-up of 19 ± 14 months. Left ventricular ejection fraction increased from 43 ± 13% to 50 ± 11% (P = 0.01). New York Heart Association functional status improved from 2.5 ± 0.5 to 1.9 ± 0.5 (P = 0.04)., Conclusion: Atrioventricular node ablation and HBP were successful in 95% of patients. His bundle pacing lead characteristics remained relatively stable. Left ventricular ejection fraction improved significantly during follow-up. His bundle pacing is feasible, safe and effective in pts undergoing AVNA., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.)

Background: Conduction disease is not uncommon after prosthetic valve (PV) surgery. The feasibility of His-bundle pacing (HBP) in this patient population is not well studied., Objective: The purpose of this study was to report our experience with permanent HBP in patients undergoing pacemaker implantation after PV surgery., Methods: Permanent HBP was attempted in patients with AV conduction disease after PV surgery referred for pacemaker implantation. Conduction disease was characterized as AV nodal vs infranodal. Feasibility, relationship of HBP lead to PVs, and HBP characteristics were recorded., Results: Thirty patients (47% men, age 74 ± 12 years, left ventricular ejection fraction 49% ± 11%) with AV conduction disease (100% patients; 14 with infranodal block; right bundle branch block 9, left bundle branch block 5, intraventricular conduction delay 1) underwent HBP. PVs included aortic valve replacement (AVR) in 8 patients (infranodal block 6 patients), tricuspid valve (TV) ring with mitral valve replacement or repair (MVR) in 10 patients (AV nodal block 9 patients), transcatheter aortic valve replacement (TAVR) in 4 patients (infranodal block 4 patients), and MVR alone in 6 patients. HBP was successful in 28 patients (93%) (selective HBP 50%). His bundle (HB) recruitment was unsuccessful in 2 patients with TAVR. AVR/TAVR and TV ring served as anatomic landmarks for localizing the HB. Successful sites of HBP were posterior and inferior to AVR/TAVR and distal and septal to the TV ring. Baseline QRSd improved from 124 ± 32 ms to 118 ± 20 ms (P = .39). HBP threshold at implant was 1.45 ± 1 V at 1 ms., Conclusion: Permanent HBP was feasible in 93% of patients with PVs. Patients with AVR/TAVR predominantly developed infranodal block compared to AV nodal block in patients with TV ring/MVR. Location of PV might serve as a landmark for identifying the site of the HB., (Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)