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Background Left bundle branch area pacing (LBBaP) is a new physiological pacing strategy that produces comparable clinical effects to His bundle pacing (HBP). Objective The purpose of this study was to investigate the immediate clinical outcomes of LBBaP vs RVP. Methods and Results From April 2018 to September 2018, we included 44 patients under continuous pacemaker implantation. Patients were randomly divided into the LBBaP group and conventional RVP group. Compared to the RVP group, the LBBaP group displayed significantly increased operative (90.10 ± 19.68 minutes vs 61.57 ± 6.62 minutes, P < .001) and X‐ray exposure times (15.55 ± 5.62 minutes vs 4.67 ± 2.06 minutes, P < .001). The lead threshold of the LBBaP group was increased (0.68 ± 0.20 mV vs 0.51 ± 0.0 mV, P = .001), while the R‐wave amplitude and ventricular impedance did not significantly differ between the two groups. The conventional RVP procedure significantly widened the QRS complex (93.62 ± 8.28 ms vs 135.19 ± 12.21 ms, P = .001), whereas the LBBaP had no effect on QRS complex (130.13 ± 43.30 ms vs 112.63 ± 12.14 ms, P = .904). Furthermore, the LBBaP procedure significantly narrowed the QRS complex in patients with left bundle branch block (LBBB) (168.43 ± 38.870 ms vs 119.86 ± 6.69 ms, P = .019). Conclusion LBBaP is a new physiological, safe and effective pacing procedure with a high overall success rate. Compared to conventional RVP, LBBaP can correct LBBB, thereby improving cardiac electrical dyssynchrony.

Several studies have reported the adverse effects of right ventricular apical pacing. Permanent His bundle pacing is proved to be the most physiological. But it can be technically difficult sometimes. One recent large multicenter randomized trial showed that pacing from left ventricular apex or mid-lateral wall has the greatest potential to prevent pacing-induced reduction of cardiac pump function (by maintaining left ventricular mechanical synchrony) and, therefore, can be considered as physiological site. In our study, we have wanted to see the outcome of left ventricular pacing through coronary sinus branch with active fixation bipolar lead as a routine pacing technique in patients with symptomatic left bundle branch block. In our study we have recruited 27 patients for left ventricular pacing through coronary sinus branch (as done in cardiac resynchronization therapy) with active fixation bipolar lead and 33 patients for right ventricular apical pacing (control) and compared left ventricular pacing with right ventricular apical pacing in patients with history of syncope with left bundle branch block in baseline electrocardiography who presented with atrio-ventricular block or prolonged HV interval (≥ 70 ms) on electrophysiology study in term of procedure and fluoroscopy time and short-term lead performance and left ventricular function. The results of our study showed that left ventricular pacing through a tributary of coronary sinus is associated with shortened QRS duration (21.10 ± 3.92 ms) and better LV function (higher left ventricular ejection fraction 64.00 ± 3.03 vs. 59.73 ± 6.73 and lower left ventricular diastolic internal diameter 4.58 ± 0.32 vs. 5.23 ± 0.40 cm) in comparison to right ventricular apical pacing. However, the total procedure time and fluoroscopy time was significantly higher (73.75 ± 11.02 vs. 63.32 ± 6.06 min and 7.08 ± 1.48 vs. 5.02 ± 1.39 min, respectively) in left ventricular pacing group. The results of this study indicate that transvenous left ventricular epicardial pacing may be an option for physiological pacing in patients with symptomatic left bundle branch block.

Conventional right ventricular (RV) pacing, particularly RV apical pacing, can have deleterious effects on cardiac function. Long-term RV apical pacing has been associated with increased risk of atrial fibrillation, hospitalization for heart failure, pacing-induced cardiomyopathy and associated death. His bundle pacing (HBP) results in physiological ventricular activation and has generated tremendous research interest and enthusiasm. By stimulating the His–Purkinje network directly, HBP results in synchronized ventricular activation, which might translate into improved clinical outcomes compared with dyssynchronous ventricular activation with RV apical pacing. HBP can also overcome bundle branch block patterns, and data are accumulating on the benefit of HBP for cardiac resynchronization therapy. In this Review, we summarize the anatomy of the His bundle and early clinical observations, implantation techniques and available outcome data associated with permanent HBP. We also highlight the challenges with HBP and the need for additional tools and more randomized data before widespread application of permanent HBP.

BackgroundThere is currently no particularly effective strategy for patients with persistent atrial fibrillation accompanying heart failure with preserved ejection fraction (HFpEF), especially with recurrent atrial fibrillation after ablation. In this study, we will evaluate a new treatment strategy for patients with persistent atrial fibrillation who had at least two attempts (≧2 times) of radio-frequency catheter ablation but experienced recurrence, and physiologic conduction was reconstructed after atrioventricular node ablation or drug therapy, to control the patient's ventricular rate to maintain a regular heart rhythm, which is called His–Purkinje conduction system pacing (HPCSP) with atrioventricular node ablation.Methods and resultsThis investigator-initiated, multicenter prospective randomized controlled trial aimed to recruit 296 randomized HFpEF patients with recurrent atrial fibrillation. All the enrolled patients were randomly assigned to the pacing group or the drug treatment group. The primary endpoint is differences in cardiovascular events and clinical composite endpoints (all-cause mortality) between patients in the HPCSP and drug-treated groups. Secondary endpoints included heart failure hospitalization, exercise capacity assessed by cardiopulmonary exercise tests, quality of life, echocardiogram parameters, 6-minute walk distance, NT-ProBNP, daily patient activity levels, and heart failure management report recorded by the CIED. It is planned to compete recruitment by the end of 2023 and report in 2025.ConclusionsThe study aims to determine whether His–Purkinje conduction system pacing with atrioventricular node ablation can better improve patients' symptoms and quality of life, postpone the progression of heart failure, and reduce the rate of rehospitalization and mortality of patients with heart failure.Clinical trial registration number: ChiCTR1900027723, URL:http://www.chictr.org.cn/edit.aspx?pid=46128&htm=4

Cardiac physiologic pacing, also known as cardiac resynchronization therapy, is indicated in patients with heart failure, reduced left ventricular ejection fraction (LVEF) of 50% or less, and either a high (or anticipated high) ventricular pacing burden or a wide QRS complex. Traditionally, physiologic pacing has been achieved with biventricular pacing with a right ventricular lead and a coronary sinus branch lead. Randomized trials involving more than 10,000 patients with heart failure have shown clinical, exercise, and quality-of-life benefits associated with biventricular pacing, as well as improved LVEF and reduced mitral regurgitation and ventricular volumes. These benefits are greatest in patients with left bundle-branch block and a QRS duration of 150 msec or longer. Recent studies support targeting the His bundle or left bundle branch as an alternative cardiac physiologic pacing strategy. Ongoing randomized trials are expected to more clearly define the comparative efficacy and safety of conduction system pacing as compared with biventricular pacing. This review summarizes cardiac physiologic pacing for heart failure, highlighting benefits of biventricular pacing and emerging evidence for His-bundle and left bundle-branch pacing to improve function and outcomes.

Left bundle branch area pacing (LBBAP) overcomes ventricular dyssynchrony induced by conventional right ventricular pacing (RVP). Despite QRS duration (QRSd) being the standard ECG marker for biventricular synchrony, it lacks insights into the ventricular activation sequence. Our aim is to assess biventricular synchrony by characterizing the ventricular activation sequence and introducing robust markers using the 12-lead ECG. A prospective single-center study was conducted, involving patients with pacemaker indication due to bradycardia. Patients were divided into LBBAP and RVP, and classified by baseline-QRS morphology. To assess biventricular synchrony, low frequency-based QRS analysis was performed to compute the ventricular activation sequence and precordial activation delay (pAD). Additional QRS markers including QRSd, QRS60, and QRS area (QRSa) were calculated. A total of 176 patients (107 LBBAP, 69 RVP) were included. The paced ventricular activation sequence indicated a more physiological pattern after LBBAP than RVP, with lower pAD values in narrow QRS, RBBB, and LBBB subgroups [ − 10( − 20,14) vs. 26(5, 39) ms;  − 18( − 30,  − 8) vs. 34(26, 55) ms; 10( − 14, 25) vs. 32(12, 48) ms] ( p  < 0.01). In all subgroups, QRS60 showed lower values after LBBAP than RVP [52(41, 62) vs.73(65, 80) ms; 60(55, 66) vs. 77(67, 83) ms; 59(53, 64) vs. 77(74, 82) ms] ( p  < 0.01) and QRSa were also lower [53(38, 66) vs. 121(92, 143) μVs; 60(50, 89) vs. 124(97, 159) μVs; 62(52, 80) vs. 133(99, 148) μVs] ( p  < 0.01). pAD provides valuable insights into ventricular activation beyond paced-QRSd. Together with QRS60 and QRSa, pAD could be a promising tool to assess biventricular synchrony.

BackgroundLeft bundle branch area pacing (LBBAP) has emerged as an alternative to biventricular pacing (BVP) for cardiac resynchronization therapy (CRT). We aimed to compare the morbidity and mortality associated with LBBAP versus BVP in patients undergoing CRT implantation.MethodsConsecutive patients who received CRT from two high-volume implantation centers were retrospectively recruited. The primary endpoint was a composite of all-cause death and heart failure hospitalization, and the secondary endpoint was all-cause death.ResultsA total of 491 patients receiving CRT (154 via LBBAP and 337 via BVP) were included, with a median follow-up of 31 months. The primary endpoint was reached by 21 (13.6%) patients in the LBBAP group, as compared with 74 (22.0%) patients in the BVP group [hazard ratio (HR) 0.70, 95% confidence interval (CI) 0.43–1.14, P = 0.15]. There were 10 (6.5%) deaths in the LBBAP group, as compared with 31 (9.2%) in the BVP group (HR 0.91, 95% CI 0.44–1.86, P = 0.79). No significant difference was observed in the risk of either the primary or secondary endpoint between LBBAP and BVP after multivariate Cox regression (HR 0.74, 95% CI 0.45–1.23, P = 0.24, and HR 0.77, 95% CI 0.36–1.67, P = 0.51, respectively) or propensity score matching (HR 0.72, 95% CI 0.41–1.29, P = 0.28, and HR 0.69, 95% CI 0.29–1.65, P = 0.40, respectively).ConclusionLBBAP was associated with a comparable effect on morbidity and mortality relative to BVP in patients with indications for CRT.HighlightsLeft bundle branch area pacing (LBBAP) was associated with a comparable effect on morbidity and mortality relative to biventricular pacing (BVP) in patients with indications for cardiac resynchronization therapy (CRT).LBBAP may serve as a promising alternative to BVP for CRT to improve morbidity and mortality among heart failure patients.Randomized controlled clinical trials with adequate sample size are justified to confirm these findings.

Introduction Left bundle branch (LBB) pacing (LBBP) demonstrates clinical potential but faces challenges in confirming selective capture via dynamic electrogram (EGM) criteria. Case report A 69-year-old male with a complete atrioventricular block underwent LBBP implantation. Real-time EGM monitoring (high-pass/low-pass filters: 200/500 Hz) revealed an abrupt shortening of stimulus-to-V6 R-wave peak time (Sti-V6 RWPT) from 87 to 69 ms during lead deployment, indicating a transition from septal pacing to LBBP. Output reduction (1.6 V → 1.5 V/0.5 ms) eliminated myocardial excitation notches, yielding isoelectric EGMs confirming selective LBB capture. Further output reduction (1.4 V → 1.3 V/0.5 ms) prolonged Sti-V6 RWPT to 90 ms with an isoelectric interval, suggesting fascicular-level conduction delay. Conclusion This case report illustrates the electrophysiological features of a diseased conduction system via dynamic EGM analysis, despite technical limitations such as signal artifacts. While EGM morphological patterns assist in differentiating pacing modalities, further validation of these electrophysiological observations is necessary.

Left bundle branch pacing (LBBP) is an emerging physiological pacing technique characterized by stable pacing parameters and a narrower QRS duration. This study aims to compare the long-term efficacy and safety of biventricular pacing (BIVP) and LBBP in patients with heart failure with reduced ejection fraction (HFrEF) and complete left bundle branch block (CLBBB). A retrospective analysis was conducted on 35 patients with chronic HFrEF accompanied by CLBBB treated at our center from April 2018 to October 2022. The patients were divided into two groups based on the surgical technique: the LBBP group and the BIVP group. Postoperative follow-up data were collected, including pacing parameters, QRS duration, echocardiographic indices (left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular ejection fraction (LVEF), mitral and tricuspid regurgitation), NT-proBNP levels, and New York Heart Association (NYHA) classification. n addition, postoperative complications, heart failure readmission rates, and mortality rates were observed. 35 patients were recruited, 18 for LBBP and 17 for BIVP. The LBBP group demonstrated significantly lower pacing thresholds and impedance at 12 months post-surgery compared to the BIVP group ( p  < 0.05). The QRS duration in the LBBP group was significantly narrower than that in the BIVP group at 6, 12, and 24 months ( p  < 0.05). At 24 months post-surgery, LVEDD and LVESD were significantly lower in the LBBP group than those in the BIVP group ( p  < 0.05). No significant differences were observed between groups in response rates, tricuspid and mitral regurgitation, NYHA class, NT-proBNP levels, all-cause mortality, or heart failure rehospitalization rates ( p  > 0.05). LBBP may be a relatively safe and effective resynchronization therapy, serving as a complementary approach to BIVP for patients with HFrEF and CLBBB.

Left bundle branch area pacing is a recent technique gaining rapid acceptance due to its broader target area and excellent electrical parameters. The aim of this study was to demonstrate the feasibility of left bundle branch area pacing in children and share short-term results. A retrospective study conducted at a single centre between December 2021 and April 2024 involved 19 children who underwent left bundle branch area pacing using Select Secure leads. The study included echocardiographic evaluations, pacing parameters, and follow-up outcomes. The cohort comprised 10 males and 9 females. Median age was seven years (range 2-18), and median weight was 38 kg (range 13-56). All patients had complete atrioventricular block, with seven having isolated congenital complete atrioventricular block and 12 postoperative complete atrioventricular block. In nine patients, transitioning from epicardial to endocardial pacing resulted in ventricular dysfunction due to chronic right ventricular pacing. The remaining patients received left bundle branch area pacing initially. One patient underwent implantation in a septal position close to the left bundle due to left bundle branch area pacing infeasibility. The median post-procedure QRS duration was 92 msec (range 80-117). Median R wave amplitude, threshold, and impedance values were 14.7 mV (range 13.3-16.8), 0.7 mV (range 0.5-1.1), and 728 ohms (range 640-762), respectively. Atrioventricular (DDD mode) leads were implanted in 10 patients, and ventricular leads (VVIR mode) were implanted in nine patients. Median fluoroscopy dose was 18.7 mGy (13.5-34.52). Left bundle branch area pacing can be safely conducted in paediatric patients exhibiting a narrow QRS duration and stable pacing parameters.