Narrow QRS ectopy with concealed connections from a para-Hisian origin to the proximal left fascicles.

INTRODUCTION: Catheter ablation of ectopy originating from the vicinity of the His bundle can be challenging. METHODS AND RESULTS: We report a case of a 33-year-old man with narrow QRS ectopy with preferential conduction from a para-Hisian origin to the proximal left fascicles, which was successfully eliminated by radiofrequency ablation in the right coronary cusp, guided by ultrahigh-resolution mapping of the His bundle, bundle branch, and fascicular electrograms. CONCLUSION: Some narrow QRS ectopy may originate from the vicinity of the conduction system, instead of the "true" conduction system, and have concealed connections from its origin to the conduction system.

Comparison of clinical outcomes between transthoracic echocardiography- and X-ray-guided left bundle branch pacing for bradycardia: A randomized controlled trial.

INTRODUCTION: Left bundle branch pacing (LBBP) is a physiological pacing modality. However, the long procedure and fluoroscopy time of LBBP is still a problem. This study aims to compare the clinical outcomes between transthoracic echocardiography (TTE)- and X-ray-guided LBBP. METHODS: This is a single-center, prospective, randomized controlled study. Consecutive patients who underwent LBBP in our team from June 2022 to November 2022 were enrolled. Procedure and fluoroscopy time, pacing parameters, electrophysiological and echocardiographic characteristics, as well as complications were recorded at implantation and during follow-up. RESULTS: In this study, 60 patients were enrolled and divided into two groups: 30 patients were allocated to the X-ray group and the remaining 30 to the TTE group. There was no significant difference in the success rate between the two groups (86.7% vs. 76.7%, p = .317). The procedure time of TTE group was comparable to that of the X-ray group (9.0 vs. 12.0 min, p = .063). However, the fluoroscopy time in the TTE group was significantly lower than that of the X-ray group (2.5 vs. 5.0 min, p = .002). There were no statistically significant differences in pacing parameters, electrophysiological and echocardiographic characteristics, or complications between the two groups at implantation and during follow-up. CONCLUSION: TTE-guided LBBP is a feasible and safe method. Compared with X-ray, TTE showed a comparable success rate and procedure time, but it could significantly reduce the fluoroscopy time of LBBP.

Result of the left bundle branch area pacing data collection registry, an international multicenter study of conduction system pacing with a Tendril STS 2088 stylet-driven lead.

INTRODUCTION: Left bundle branch area (LBBA) pacing (LBBAP) has been proposed as an alternative therapy option in patients indicated for cardiac pacing to treat bradycardia or heart failure. The aim of the study was to evaluate the safety and effectiveness of LBBAP in patients implanted with a Tendril 2088 stylet-driven lead. METHODS: The international retrospective data collection registry included 11 sites from 5 countries globally. Patients with attempted implants of the Tendril lead in the LBBA were followed for at least 6 months post the implant attempt. The primary safety and efficacy endpoints were freedom from LBBAP lead-related serious adverse events and the composite of LBBA capture threshold of ≤2.0 V and R-wave amplitudes ≥5 mV (or ≥value at implant), respectively. RESULTS: Of 221 patients with attempted implants of the Tendril 2088 lead in the LBBA, 91.4% (202/221) had successful implants for LBBAP. Regardless of the LBBAP implant success, all patients were followed for at least 6 months (8.7 ± 7.3 months). Baseline characteristics: 44% female, 84% ≥65 years old, 34% coronary artery disease, and 86% of primary indications for pacemaker implant. Both primary safety and effectiveness endpoints were met (freedom from LBBAP lead-related serious adverse device effects of 99.5% and electrical performance composite success rate of 93%). The capture thresholds in LBBAP at implant and 6 months were 0.8 ± 0.3 V@0.4 ± 0.1 ms and 0.8 ± 0.3 V@0.4 ± 0.1 ms. The rate of patients with capture threshold rise ≥1 V was 1.5% through 6 months. The R-wave amplitudes in LBBAP at implant and 6 months were 9.3 ± 3.2 mV and 10.6 ± 3.0 mV. CONCLUSIONS: This large multicenter study demonstrates that the stylet-driven Tendril™ STS 2088 lead is safe and effective for LBBAP with high success and low complication rates.

Left bundle branch area pacing in heart failure: A systematic review and meta-analysis with meta-regression.

INTRODUCTION: Left bundle branch area pacing is an alternative to biventricular pacing. In this study, we aim to summarize the available evidence on the feasibility, efficacy, and safety of left bundle branch block area pacing (LBBAP). OBJECTIVES: The study summarizes the available evidence on the feasibility, efficacy, and safety of left bundle branch block area pacing (LBBAP). BACKGROUND: Cardiac resynchronization therapy (CRT) reduced mortality and hospitalizations in heart failure (HF) patients with a left ventricular ejection fraction (LVEF) ≤ 35% and concomitant LBBB. Recently LBBAP has been studied as a more physiological alternative to achieve CRT. METHOD: A search of PubMed, EMBASE, and Cochrane databases were performed to identify studies examining the role of LBBAP for CRT in heart failure. Comprehensive meta-analysis version 4 was used for meta-regression to examine variables that contribute to data heterogeneity. RESULT: Eighteen studies, 17 observational and one randomized controlled trial (RCT) were examined. A total of 3906 HF patients who underwent CRT (2036 LBBAP vs. 1870 biventricular pacing [BVP]) were included. LBBAP was performed successfully in 90.4% of patients. Compared to baseline, LBBAP was associated with a reduction in QRS duration (MD: -47.23 ms 95% confidence interval [CI]: -53.45, -41.01), an increase in LVEF (MD: 15.22%, 95% CI: 13.5, 16.94), and a reduction in NYHA class (MD: -1.23, 95% CI: -1.41, -1.05). Compared to BVP, LBBAP was associated with a significant reduction in QRS duration (MD: -20.69 ms, 95% CI: -25.49, -15.88) and improvement in LVEF (MD: 4.78%, 95% CI: 3.30, 6.10). Furthermore, LBBAP was associated with a significant reduction in HF hospitalization (odds ratio [OR]: 0.44, 95% CI: 0.34, 0.56) and all-cause mortality (OR: 0.67, 95% CI: 0.52, 0.86) compared to BVP. CONCLUSION: LBBAP was associated with improved ventricular electrical synchrony compared to BVP, as well as better echocardiographic and clinical outcomes.

Mid-term performance of His bundle pacing and usefulness of backup leads.

Ventricular backup leads may be considered in selected patients with His bundle pacing (HBP), but it remains unknown to what extent this is useful. A total of 184 HBP patients were studied. At last follow-up, 147 (79.9%) patients retained His bundle capture at programmed output. His bundle pacing lead revision was performed in 5/36 (13.9%) patients without a backup lead and in 3/148 (2.0%) patients with a backup lead (P = 0.008). One patient without a backup lead had syncope due to atrial oversensing. Thus, implantation of ventricular backup leads may avoid lead revision and adverse events in selected HBP patients.

Current of injury amplitude during left bundle branch area pacing implantation: impact of filter settings, ventricular pacing, and lead type.

AIMS: Monitoring current of injury (COI) during left bundle branch area pacing (LBBAP) implantation is useful to evaluate lead depth. Technical aspects for recording COI amplitude have not been well studied. Our aims were to evaluate the impact of high-pass filter settings on electrogram recordings during LBBAP implantation. METHODS AND RESULTS: Consecutive patients with successful LBBAP implantation had unipolar recordings of COI at final lead position at different high-pass filter settings (0.01-1 Hz) from the tip electrode during sensing and pacing, and from the ring electrode during sensing. Duration of saturation-induced signal loss was also measured at each filter setting. COI amplitudes were compared between lumenless and stylet-driven leads. A total of 156 patients (96 males, aged 81.4 ± 9.6 years) were included. Higher filter settings led to significantly lower COI amplitudes. In 50 patients with COI amplitude < 10 mV, the magnitude of the drop was on average 1-1.5 mV (and up to 4 mV) between 0.05 and 0.5 Hz, meaning that cut-offs may not be used interchangeably. Saturation-induced signal loss was on average 10 s at 0.05 Hz and only 2 s with 0.5 Hz. When pacing was interrupted, the sensed COI amplitude varied (either higher or lower) by up to 4 mV, implying that it is advisable to periodically interrupt pacing to evaluate the sensed COI when reaching levels of ∼10 mV. Lead type did not impact COI amplitude. CONCLUSION: High-pass filters have a significant impact on electrogram characteristics at LBBAP implantation, with the 0.5 Hz settings having the most favourable profile.

Extraction of lumenless pacing leads from the His bundle and left bundle branch area: outcomes of the high-volume centre.

AIMS: The application of conduction system pacing (CSP) in clinical practice is growing, and the need for lead extraction will also increase. The data on outcomes and safety of CSP lead extraction are limited. The aim of this study was to assess procedural outcomes and safety of CSP lead removal. METHODS AND RESULTS: Forty-seven patients from the EXTRACT Registry with the indication for CSP lead removal were enrolled in the study conducted at the Department of Electrocardiology in Katowice, Poland. Extraction technique, outcomes, safety, and complication were evaluated. Forty-three (91.5%) leads were successfully removed, and 41 (87.2%) were removed with traction only. The dwelling time of 28 extracted leads was longer than 1 year, and the oldest extracted lead was implanted for 89 months. Seven (14.9%) leads were removed from the left bundle branch (LBB) area and 36 from the His bundle (HB). Transient complete atrioventricular block occurred during the procedure in two patients. In 27 out of 31 attempts (87.1%), new CSP leads were implanted: nine (33.3%) HB pacing leads and 18 (66.7%) LBB area pacing leads. CONCLUSION: The CSP lead extraction is safe and feasible with a low complication rate and high rate of CSP lead reimplantation.

Septal venous channel perforation during left bundle branch area pacing: a prospective study.

AIMS: To characterize the diagnosis, frequency, and procedural implications of septal venous channel perforation during left bundle branch area pacing (LBBAP). METHODS AND RESULTS: All consecutive patients undergoing LBBAP over an 8-month period were prospectively studied. During lead placement, obligatory septal contrast injection was performed twice, at initiation (implant entry zone) and at completion (fixation zone). An intuitive fluoroscopic schema using orthogonal views (left anterior oblique/right anterior oblique) and familiar landmarks is described. Using this, we resolved zonal distribution (I-VI) of lead position on the ventricular septum and its angulation (post-fixation angle θ). Subjects with and without septal venous channel perforation were compared. Sixty-one patients {male 57.3%, median age [interquartile range (IQR)] 69.5 [62.5-74.5] years} were enrolled. Septal venous channel perforation was observed in eight (13.1%) patients [male 28.5%, median age (IQR) 64 (50-75) years]. They had higher frequency of (i) right-sided implant (25% vs. 1.9%, P = 0.04), (ii) fixation in zone III at the mid-superior septum (75% vs. 28.3%, P = 0.04), (iii) steeper angle of fixation-median θ (IQR) [19 (10-30)° vs. 5 (4-19)°, P = 0.01], and (iv) longer median penetrated-lead length (IQR) [13 (10-14.8) vs. 10 (8.5-12.5) mm, P = 0.03]. Coronary sinus drainage of contrast was noted in five (62.5%) patients. Abnormal impedance drops during implantation (12.5% vs. 5.7%, P = NS) were not significantly different. CONCLUSION: When evaluated systematically, septal venous channel perforation may be encountered commonly after LBBAP. The fiducial reference framework described using fluoroscopic imaging identified salient associated findings. This may be addressed with lead repositioning to a more inferior location and is not associated with adverse consequence acutely or in early follow-up.

Observational study of left bundle branch area pacing: implantation of the solia S lead using the selectra 3D sheath at an inclined angle.

BACKGROUND: Left Bundle Branch Area Pacing (LBBaP) is a cardiac pacing technique designed to mimic the natural conduction system of the heart. Traditional right ventricular apical pacing has been associated with increased risks of heart failure and atrial fibrillation. This study investigates the stability and safety of LBBaP using the Selectra 3D sheath (Biotronik) with an inclined angle for implanting the Solia S lead (Biotronik, SE & Co, KG). METHODS: A single-center retrospective study was conducted on 25 patients who underwent LBBaP implantation using the Selectra 3D sheath at our hospital. The procedure involved inserting the Solia S lead into the interventricular septum at an inclined angle. Surgical and postoperative data were collected, including the success rate, depth and angle of electrode insertion, complications, and follow-up data. RESULTS: The success rate of LBBaP implantation was 92%. The length of electrode insertion into the interventricular septum ranged from 12 to 23.0 mm, with an average of 18.1 ± 3.08 mm. The angle formed between the electrode and the septum ranged from 0° to 57.3°, with an average of 35.14°±14.31°. During the 3-month follow-up period, pacing parameters remained stable, and no complications were reported. CONCLUSIONS: LBBaP implantation using the Selectra 3D sheath with an inclined angle for the Solia S implantation demonstrates stability and safety. The procedure boasts a high success rate and offers an effective option for LBBaP implantation.

Permanent left bundle branch area pacing improves mitral regurgitation and cardiac function in patients with right bundle branch block.

BACKGROUND: Permanent left bundle branch area pacing (LBBAP) has been established as an effective means to correct left bundle branch block. Right bundle branch block (RBBB), emerge as a distinct form of cardiac conduction abnormality, can be seen in the context of LBBAP procedure. However, the correction potential of LBBAP in patients with RBBB remains largely unexplored. OBJECTIVE: The objective of this study was to evaluate the efficacy and safety of permanent LBBAP in patients with RBBB. METHODS: Ninety-two consecutive patients who underwent successful permanent LBBAP were recruited from May. 2019 to Dec. 2022 in Fuwai Central China Cardiovascular Hospital. Among them, 20 patients with RBBB were included in our analysis. These patients were followed up at 1, 3, 6 and 12 months post-LBBAP. The QRS duration (QRSd) on the V1 lead of the 12-lead elctrocardiogram was measured and compared before and after the LBBAP procedure. Additionally, mitral regurgitation, tricuspid regurgitation and cardiac function were assessed using transthoracic echocardiography, specifically focusing on left ventricular ejection fraction (LVEF) and mitral regurgitation severity. The acute pitfills and delayed complications associated with the LBBAP procedure were recorded to evaluate its safety. SPSS 23.0 was used to perform statistical analysis with Student's t test or one way ANOVA or nonparametric tests (paired Wilcoxon test). A p value less than 0.05 was defined as significant. RESULTS: The demographic breakdown of the RBBB cohort revealed a mean age of 66.35 ± 11.55 years, 60% being male. Comorbidities were prevalent, including severe atrioventricular block (AVB) in 75%, sick sinus syndrome (SSS) in 20%, heart failure in 25%, atrial fibrillation in 30%, coronary heart diseases in 45%, hypertension in 35%, and diabetes mellitus in 15%. Regarding the LBBAP procedure, the average operation time was 106.53 ± 2.72 min, with 45% of patients (9 individuals) requiring temporary cardiac pacing during the surgery. Notably, the LBBAP procedure significantly narrow the QRS duration in RBBB patients, from 132.60 ± 31.49ms to 119.55 ± 18.58 ms (P = 0.046). Additionally, at the 12-month follow-up, we observed a marked improvement in LVEF, which increased significantly from 55.15 ± 10.84% to 58.5 ± 10.55% (P = 0.018). Furthermore, mitral regurgitation severity improved, with a median reduction from 4.46 (0.9, 7.3) to 2.29 (0, 3.49) cm2 (P = 0.033). Importantly, no cases of ventricular septum perforation or pericardial effusion were reported during the LBBAP procedure or during the follow-up period. CONCLUSION: LBBAP provides an immediate reduction in QRS duration for patients suffering from RBBB, accompanied by improvements in mitral regurgitation and cardiac function as evident in the 12-month follow-up period.

Upgrade from leadless to transvenous pacemaker with left bundle branch area pacing: A case report.

An 80-years-old patient with permanent atrial fibrillation and symptomatic, paroxysmal atrioventricular blocks (AVBs) underwent leadless pacemaker (L-PM) implantation. Seven years after implantation, as a consequence of a progression of the AVB towards a persistent form, resulting in an increased need for pacing, he developed a pacing-induced cardiomyopathy. He then underwent a successful upgrade from L-PM to a transvenous pacemaker (T-PM) with left bundle branch area pacing (LBBAP). The L-PM did not interfere with the T-PM and was turned off and abandoned. One month after the upgrading the patient showed a significant improvement in cardiac function and functional capacity.

Outcomes of combined left bundle branch area pacing with atrioventricular nodal ablation in patients with atrial fibrillation and pulmonary disease.

INTRODUCTION: Concomitant left bundle branch area pacing (LBBAP) with atrioventricular (AV) nodal ablation is emerging as a viable management option in atrial fibrillation refractory to medical management. Its viability in patients with pulmonary disease and atrial fibrillation is unknown. METHODS AND RESULTS: This is a retrospective, observational cohort study in consecutive patients who underwent concomitant LBBAP with AV nodal ablation with advanced pulmonary disease at the Cleveland Clinic Fairview Hospital between January 2019 and January 2023. Patient characteristics, comorbidities, and medication use were extracted via chart review. Rates of hospitalizations, medication use, and structural disease seen on echocardiography were compared before and after the procedure. There were 27 patients with group 3 pulmonary hypertension who underwent the procedure. In the 24 months preprocedure, there were 114 admissions for heart failure or atrial fibrillation compared to 9 admissions postprocedure (p < .001). Mean follow up was 17.3 ± 12.1 months. There were no significant complications or lead dislodgements. Echocardiographic characteristics were similar prior to and after pacemaker implantation. Use of medications for rate and rhythm control was common preprocedure, and was reduced dramatically postprocedure. CONCLUSION: This small, retrospective cohort study suggests concomitant LBBAP with AV nodal ablation may be safe and efficacious for management of atrial fibrillation in patients with advanced pulmonary disease.

The impact of His bundle location and direction on the efficacy and safety of ablation.

BACKGROUND: The impact of the His bundle location and distance from the ablation site on ablation efficacy and complication risk remains unexplored. We determined the correlation between age, height, body mass index (BMI), and the His bundle location, and whether the distance between the His bundle and ablation target (DHIS-ABL) affects ablation safety and efficacy. METHODS: Overall, 346 patients with atrioventricular nodal re-entrant tachycardia (AVNRT) and 96 with atrioventricular re-entrant tachycardia (AVRT) were retrospectively analyzed. The distance between the His bundle and the coronary sinus ostium (DHis-CS), the height of the His bundle (HHIS), and DHIS-ABL were measured. Electrocardiograms were obtained 3 months post-ablation to assess recurrence and complications. RESULTS: Multiple linear regression showed that HHIS was negatively correlated with age in both groups. In AVNRT patients, DHIS-ABL was associated with age, height, and BMI; DHIS-CS was only negatively correlated with age. In AVRT patients, there was no significant correlation between the DHIS-ABL and age, height, or BMI. The recurrence rates in the AVNRT and AVRT groups were 0.9% and 8.7%, respectively. Subgroup analysis showed that patients with DHIS-ABL ≤ 10 mm had a higher recurrence rate than those with DHIS-ABL > 10 mm (p = .013). The incidence of third-degree atrioventricular block (AVB) complications was 0.2%. CONCLUSIONS: HHIS was negatively correlated with age but not with height and BMI. The DHIS-ABL correlated with age, height, and BMI in AVNRT patients. A short DHIS-ABL led to a higher rate of supraventricular tachycardia recurrence; whether this affects AVB risk warrants further studies with larger sample sizes.

Gradual development of left bundle branch current of injury during left bundle branch pacing lead implantation.

A larger left bundle branch (LBB) potential or LBB current of injury (COI) indicates a low LBB capture threshold in LBB pacing. During LBB pacing in an 85-year-old woman, achieving a low LBB capture threshold did not initially present with a larger LBB potential or LBB COI, but rather with a new initial negative deflection in a ventricular electrogram. LBB COI gradually developed over 7 min thereafter, which suggested that the lead tip had reached the left ventricular subendocardium. Therefore, this negative deflection may be the first sign to avoid further lead rotation.

His potential injury as the end point of screwing by a continuous recording technique in His bundle pacing: A case report.

BACKGROUND: His bundle pacing (HBP) engaged electrical activation of both ventricles by stimulating the His-Purkinje network, which could avoid marked ventricles dyssynchrony. The lead was given three to five clockwise rotations at the site with the His potential to anchor the interventricular septum. In 2018, the Multicenter His Bundle Pacing Collaborative Working Group recommended that the His bundle capture threshold should be lower than 2.5 V/1 ms in non-pacing-dependent patients, and pacing-dependent patients should have a lower adjacent ventricular capture threshold as self-backup. Therefore, to avoid safety issues such as loss of capture caused by increased threshold, we believe that more stringent criteria should be adopted in patients with atrioventricular block (AVB). In previous studies, the connection cable needed to be disconnected during the screwing. When the procedure was finished, the performer found that the patients with His bundle injury could obtain a lower threshold than those without His bundle injury. Although no studies of new bundle branch block (BBB) or AVB by the acute His bundle injury was reported. However, It is worrying that the damage of His bundle seems random during the procedure. How to balance avoiding severe injury with a lower capture threshold? At present, we report a case of light His injury and lower His capture threshold under continuous intracardiac electrocardiogram monitoring.

Impact of Pulsed Electric Field Ablation on His Bundle Conduction: A Preclinical Canine Study.

BACKGROUND Pulsed field ablation (PFA), as a non-thermal ablation modality, has received increasing attention. The aim of this study was to evaluate the effect of PFA upon His bundle via its implementation with different voltages on the maximum His bundle potential in canines, providing scientific basis for clinical application. MATERIAL AND METHODS Pulsed electrical field energy was delivered from a ablation catheter to the maximum His potential of 7 dogs, followed by a series of electrogram and histology assessments. RESULTS The baseline AH and HV intervals were 55.3±3.7 ms (range, 53.0-59.0 ms), and 34.9±1.3 ms (range, 34.0-36.0 ms), respectively, which were elevated to 65.0±5.4 ms (range, 59.0-70.0 ms) and 35.7±2.7 ms (range, 34.0-37.0 ms) after PFA. Before ablation and immediately after the recovery of third-degree AVB, the AH interval was prolonged (P<0.05) while the HV interval remained unchanged (P>0.05). After ablation, all 7 canines experienced transient third-degree AVB, with a voltage-dependent duration. Masson staining results revealed no apparent damage in His bundle cells. CONCLUSIONS Within a certain voltage range of pulse electric field, ablation of the maximum His potential in canines can result in transient third-degree AVB, providing a new route for guiding safe ablation of para-Hisian arrhythmia.

Conduction System Pacing: Hope, Challenges, and the Journey Forward.

PURPOSE OF THE REVIEW: Cardiac pacing has evolved in recent years currently culminating in the specific stimulation of the cardiac conduction system (conduction system pacing, CSP). This review aims to provide a comprehensive overview of the available literature on CSP, focusing on a critical classification of studies comparing CSP with standard treatment in the two fields of pacing for bradycardia and cardiac resynchronization therapy in patients with heart failure. The article will also elaborate specific benefits and limitations associated with CSP modalities of His bundle pacing (HBP) and left bundle branch area pacing (LBBAP). RECENT FINDINGS: Based on a growing number of observational studies for different indications of pacing therapy, both CSP modalities investigated are advantageous over standard treatment in terms of narrowing the paced QRS complex and preserving or improving left ventricular systolic function. Less consistent evidence exists with regard to the improvement of heart failure-related rehospitalization rates or mortality, and effect sizes vary between HBP and LBBAP. LBBAP is superior over HBP in terms of lead measurements and procedural duration. With regard to all reported outcomes, evidence from large scale randomized controlled clinical trials (RCT) is still scarce. CSP has the potential to sustainably improve patient care in cardiac pacing therapy if patients are appropriately selected and limitations are considered. With this review, we offer not only a summary of existing data, but also an outlook on probable future developments in the field, as well as a detailed summary of upcoming RCTs that provide insights into how the journey of CSP continues.

Conduction latency in left bundle branch pacing in heart failure patient.

Since the introduction of left bundle branch pacing (LBBP), a search for precise parameters confirming successful capture of conduction system was conducted. Most of the proposed electrocardiographic criteria refer to patients with narrow QRS complexes. We present a patient with heart failure in whom cardiac resynchronization was achieved using conduction system pacing. While measuring left ventricular activation time, an isoelectric interval of 74 ms between stimulus and R-wave appeared resulting in prolongation of V6 RWPT to 124 ms. Considering the immediate narrowing of QRS complexes following LBBP, the observed latency most probably reflects prolonged conduction time through the His-Purkinje system.

Clinical Features and Outcomes of Long-Term Lead Performance by Left Bundle Branch Pacing.

Left bundle branch pacing (LBBP) is an emerging physiological pacing technique that expanded in recent reports. The long-term safety and feasibility of LBBP lack adequate evaluation.The study aimed to evaluate the long-term lead performance and clinical outcomes of LBBP.We retrospectively enrolled 123 consecutive patients scheduled for LBBP implantation from January to December 2018. The pacing parameters, electrocardiograms, echocardiographic measurements, and complications associated with LBBP were tracked at implant and follow-up.LBBP was successfully performed in 110 of 123 (89.4%) patients. Left ventricular end-diastolic dimension (LVEDd) and left ventricular ejection fraction (LVEF) improved from baseline in patients with reduced LVEF (n = 29; LVEDd, 55.6 ± 8.1 mm versus 63.4 ± 4.9 mm, P < 0.001; LVEF, 51.6% ± 13.6% versus 33.7% ± 5.5%, P < 0.001) while no significant change was found in patients with preserved LVEF (n = 81; LVEDd, 49.6 ± 12.0 mm versus 51.2 ± 6.0 mm, P = 0.38; LVEF, 65.8% ± 7.9% versus 65.8% ± 7.3%, P = 0.99). In seven patients, LBBP lead protuberance into the LV cavity was observed, with a mean distance between the screw tip and the LV septum of 3.0 ± 0.8 mm (range from 1.8 to 3.9 mm). The LBBP parameters remained stable.LBBP is a novel physiological, safe, and effective pacing technique for patients with atrioventricular block. Lower BMI, diabetes and thinner interventricular septum (IVS) thickness are associated with mechanical complications.

Early Experience of Left Bundle Branch Pacing with Lumenless Lead in a Single Center: A Case Series.

Left bundle branch pacing (LBBP) has been subject to increasing interest over the last few years due to its capacity for physiological conduction and its advantages compared to His bundle pacing. His bundle pacing has certain limitations, such as a small pacing area for the His bundle, a high threshold that leads to battery depletion, a low R-wave amplitude that may result in atrial or His oversensing, and ventricular signal undersensing. In this case series, four patients (two female and two male) aged 62.2 ± 8.4 years old with symptomatic sick sinus disease and no scar tissue in the interventricular septum underwent LBBP. All LBBPs were done with standard LBBP using a lumenless SelectSecure 3830 lead (Medtronic®, Minneapolis, USA) with a fixed helix. The lead parameters showed a good R-wave amplitudes (13 ± 7.4 mV) and a low threshold  (0.77 ± 0.17 V @ 0.4 ms). All patients were discharged on the next day. During follow-up period of 13.3 ± 12.9 months, all patients were well and no complications were noted. In conclusion, LBBP may be as an alternative of novel conduction pacing techniques and can be done relatively easy and safe, even with limited experience center.