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.

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.

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.

Anterior ST elevation in a patient with RBBB.

A 79-year-old male with a history of coronary artery disease presented to the Emergency Department with chest pain. ECG showed RBBB with mild ST elevation and positive T waves in I, aVL and V2. In patients with RBBB lack of ST depression and T wave inversion in the anterior leads could signify ischemia secondary to left anterior descending coronary artery occlusion. However, the patient did not have acute coronary syndrome and the presenting ECG was comparable to an ECG recorded five years earlier.

Sex differences outcomes in conduction system pacing for patients with typical left bundle branch block.

BACKGROUND: Biventricular pacing (BVP) appears to confer more pronounced advantages in women, yet the impact of conduction system pacing (CSP) remains insufficiently characterized. This investigation seeks to elucidate sex-specific disparities in clinical outcomes among patients with typical left bundle branch block (LBBB) undergoing CSP, with a particular focus on assessing contributory factors. METHODS: Consecutive patients diagnosed with nonischemic cardiomyopathy, exhibiting left ventricular ejection fraction (LVEF) ≤ 40%, and manifesting typical LBBB as Strauss criteria, underwent CSP. Subsequent longitudinal monitoring assessed improvements in LVEF and the composite endpoint of mortality or heart failure hospitalization (HFH). RESULTS: Among the included 176 patients, women (n = 84, mean age: 69.5 ± 8.8 years) displayed smaller heart size (LVEDd, 62.0 ± 8.3 mm vs. 64.8 ± 7.9 mm, P = 0.023) and shorter baseline QRSd (163.5 ± 17.7 ms vs. 169.7 ± 15.1 ms; P = 0.013) than men. Of the 171 patients who completed the follow-up, super-response was observed in 120 (70%), with a higher occurrence in women than men (78.3% vs. 62.5%, P = 0.024). The incidence of death or HFH was numerically lower in women (7.1% Vs 13%, Log-rank P = 0.216). Notably, the super-response showed a significant difference in women compared to men at the same electrocardiography and/or echocardiographic parameters value. Mediation analysis between sex and super-response revealed that LVEDd and pQRSd play an intermediary role, with the mediation proportion of 26.07% and 27.98%, respectively. CONCLUSIONS: Women may derive more benefits from CSP, and pQRSd and LVEDd partly drive this difference.

Predictors of functional mitral regurgitation improvement in patients with left bundle branch block treated with left bundle branch area pacing.

BACKGROUND: Functional mitral regurgitation (FMR) and its severity are associated with adverse outcomes in heart failure patients. This study aims to analyze the predictors of FMR improvement after successful left bundle branch area pacing (LBBAP) in patients with LVEF < 50% and complete left bundle branch block (CLBBB). METHODS: Consecutive patients with LVEF < 50% and CLBBB who underwent successful LBBAP from July 2018 to July 2023 were retrospectively identified. Significant MR was defined as regurgitation of moderate severity or greater. Patients with significant FMR were included in the analysis. FMR improvement (FMRI) was defined as a reduction of at least one grade in regurgitation severity compared to baseline at 3 months or longer follow-up. RESULTS: Among the 81 identified patients, 42 patients with significant FMR preoperatively were included. After LBBAP, QRS duration significantly shortened from 170.6 ± 18.8 ms to 114.5 ± 20.2 ms (p < .001). Significant FMR improves in approximately 76.2%, and the patients were divided into an FMRI group (n = 32) and a non-FMRI group (n = 10). Univariate analysis showed that absence of persistent atrial fibrillation, typical CLBBB, and left atrium diameter at baseline were associated with improvement of FMR after LBBAP. Of these variables, only absence of persistent atrial fibrillation remains an independent predictor in the multivariate model (OR 12.436, p = .009). CONCLUSION: LBBAP is able to improve FMR in heart failure patients who had CLBBB with LVEF < 50%. Meanwhile, the absence of persistent atrial fibrillation is an independent predictor of FMR improvement.

Impact of the Aortomitral Positional Anatomy on Atrioventricular Conduction Disorder Following Mitral Valve Surgery.

BACKGROUND: Variations in the aortomitral positional anatomy, including aortic root rotation appear to be related to variations in the location of the conduction system, including the bundle of His. However, little is known about their clinical significance. METHODS AND RESULTS: This study included 147 patients with normal ECGs who underwent mitral valve surgery. The aortomitral anatomy was classified using preoperative 3-dimensional transesophageal echocardiography, and postoperative conduction disorders, including atrioventricular block and bundle branch block, were analyzed. Variations classified as aortomitral appearance were designated as having a center appearance (85.7%, n=126/147) or lateral appearance (14.3%, n=21/147) on the basis of whether the aortic root was located at the center or was shifted to the left fibrous trigone side. Subsequently, those with a center appearance, aortic root rotation was classified as having a center rotation (83.3% [n=105/126]), in which the commissure of the left and noncoronary aortic leaflet was located at the center, lateral rotation (14.3% [n=18/126]), rotated to the left trigone side, or medial rotation (2.4% [n=3/126]), rotated to the right. The incidence of 3-month persistent new-onset conduction disorder was higher in the lateral appearance than the center appearance group (21.1% versus 5.0%; P=0.031) and higher in the lateral rotation than in the center or medial rotation groups (29.4% versus 1.0% versus 0.0%, respectively; P<0.001). CONCLUSIONS: Aortomitral variations can be classified using 3-dimensional transesophageal echocardiography. Lateral appearance and lateral rotation are risk factors for conduction disorders in mitral valve surgery.

Physical Activity Modifies the Risk of Incident Cardiac Conduction Disorders Upon Inflammation: A Population-Based Cohort Study.

BACKGROUND: Emerging evidence suggests a central role for inflammation in cardiac conduction disorder (CCD). It is unknown whether habitual physical activity could modulate the inflammation-associated risks of incident CCD in the general population. METHODS AND RESULTS: This population-based cohort was derived from the China Kailuan study, including a total of 97 192 participants without prior CCD. The end points included incident CCD and its subcategories (atrioventricular block and bundle-branch block). Systemic inflammation was indicated by the monocyte-to-lymphocyte ratio (MLR). Over a median 10.91-year follow-up, 3747 cases of CCD occurred, with 1062 cases of atrioventricular block and 2697 cases of bundle-branch block. An overall linear dose-dependent relationship was observed between MLR and each study end point (all P-nonlinearity≥0.05). Both higher MLR and physical inactivity were significantly associated with higher risks of conduction block. The MLR-associated risks of developing study end points were higher in the physically inactive individuals than in those being physically active, with significant interactions between MLR levels and physical activity for developing CCD (P-interaction=0.07) and bundle-branch block (P-interaction<0.05) found. Compared with those in MLR quartile 2 and being physically active, those in the highest MLR quartile and being physically inactive had significantly higher risks for all study end points (1.42 [95% CI, 1.24-1.63], 1.62 [95% CI, 1.25-2.10], and 1.33 [95% CI, 1.13-1.56], respectively, for incident CCD, atrioventricular block, and bundle-branch block). CONCLUSIONS: MLR should be a biomarker for the risk assessment of incident CCD. Adherence to habitual physical activity is favorable for reducing the MLR-associated risks of CCD.

[Clinical analysis of maternal autoantibody-mediated complete left bundle branch block in 9 children].

Objective: To analyze the clinical characteristics, treatment, and outcomes of children with complete left bundle branch block (CLBBB) mediated by maternal autoantibodies. Methods: A retrospective analysis was conducted on nine children diagnosed with maternal autoantibody-mediated CLBBB, treated at Beijing Anzhen Hospital and Fujian Provincial Hospital from March 2015 to August 2023. Their clinical characteristics, electrocardiographic and echocardiographic findings before and after treatment were reviewed. Paired sample t-test was used for inter-group comparison. Results: Among the mothers, 6 had positive antinuclear antibodies (ANA), 5 had anti-Sjogren syndrome antigen A antibodies, and 3 had anti-Ro-52 antibodies. The cohort included one female and eight male children, diagnosed with CLBBB at the age of 1 (2, 13) months. The positive autoantibodies in the infants, consisted with maternal antibodies, were detected within the first 3 months of life among 3 cases. Treatments included anti-heart failure therapy, myocardial nutritional support, intravenous immunoglobulin (IVIG) and glucocorticoids. Before treatment, the levels of troponin I (0.175 (0.060, 10.270) µg/L) and N-terminal pro-B-type natriuretic peptide (420 (327, 12 865) ng/L) were elevated, which normalized in most cases after treatment. Post-treatment, the QRS duration significantly shortened compared to pre-treatment ((137±15) vs.(169±25) ms, t=3.76, P<0.001), and the QTc interval significantly decreased ((433±41) vs. (514±27) ms, t=4.95, P=0.001). Before treatment, varying degrees of mitral and tricuspid regurgitation and marked interventricular septal dyskinesia were observed in echocardiography. After treatment, valve regurgitation and ventricular septum motion significantly improved, with a marked increase in left ventricular ejection fraction ((51±13)% vs. (27±6)%, t=-6.66, P<0.001). Conclusions: Maternal autoantibody-mediated CLBBB in children presents with chronic heart failure in infancy. Early treatment with anti-heart failure medications, IVIG and glucocorticoids can improve clinical symptoms.

Risk of mortality associated to chronic kidney disease in patients with complete left bundle branch block.

Chronic kidney disease (CKD) is associated with cardiac conduction defects and is a strong risk factor for heart failure. Complete left bundle branch block (cLBBB), a cardiac conduction abnormality, may have an unfavorable effect on ventricular mechanical synchrony and lead to the progression of heart failure. Once heart failure develops, it seems to act together with underlying CKD in a vicious circle. Therefore, this study aimed to explore the influence of CKD in patients with cLBBB by assessing the estimated glomerular filtration rate (eGFR). We examined a hospital-based sample of 416 adult patients with cLBBB from 2010 to 2013. The eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Cox proportional hazard models were used to estimate the hazard ratio for all-cause mortality and cardiovascular mortality. A total of 416 adult patients with a mean age of 71 ± 13 years were enrolled. The median follow-up period was 3.6 years. After adjusting for clinical, electrocardiographic parameters, and medication use, cox regression analysis showed that total mortality was significantly associated with older age (Hazard Ratio (HR) = 1.03, 95% CI = 1.01-1.05, p = 0.002), presence of congestive heart failure (HR = 2.39, 95% CI = 1.63-3.49, p < 0.001), advanced CKD (HR = 2.48, 95% CI = 1.71-3.59, p < 0.001), higher HR (HR = 1.02, 95% CI = 1.01-1.03, p < 0.001) and without use of ACEI/ARB (HR = 0.59, 95% CI = 0.41-0.85, p = 0.005) were independent predictors of the total mortality. Multivariate Cox hazard regression analysis demonstrated that, in comparison to patients lacking cLBBB, the coexistence of CKD (eGFR < 60 mL/min/1.73 m2) among those with LBBB significantly heightened the risks of both total mortality (HR ratio of 5.01 vs. 2.40) and CV death (HR ratio of 61.78 vs. 14.41) even following adjustment for clinical covariates and ECG parameters. In summary, within patients exhibiting cLBBB, the presence of CKD serves as a significant risk factor for all-cause mortality.

Left bundle branch pacing guide by uninterrupted recording of intrinsic filtered and unfiltered intracardiac electrograms.

BACKGROUND: Currently, the interrupted recording technique is commonly used to perform left bundle branch (LBB) pacing (LBBP). However, this method requires repeated testing to confirm that the LBB is captured and perforations are avoided. An automated solution may make this repetitive work easier. CASE SUMMARY: LBBP was performed using an uninterrupted recording technique in an 86-year-old woman. Lead position and LBB capture was confirmed by the characteristics of the intrinsic filtered and unfiltered intracardiac electrograms. CONCLUSION: Continuous mapping and recording technique may help achieve more accurate positioning of LBBP lead in the ventricular septum.

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.

[New pacing strategies for heart failure]. / Neue Pacing-Strategien bei Herzinsuffizienz.

In patients with a reduced left ventricular (LV) systolic function (ejection fraction < 35%) and a left bundle branch block with a QRS duration > 130 ms, cardiac resynchronization therapy (CRT) can contribute to an improvement in the quality of life and a reduction in mortality. The resynchronization is mostly achieved by pacing via an epicardial LV lead in the coronary sinus; however, this approach is often limited by the patient's venous anatomy and an increase in the stimulation threshold over time. In addition, up to 30% of patients do not respond to the intervention. New treatment approaches involve direct stimulation of the conduction system by pacing of the bundle of His or left bundle branch. This enables a more physiological propagation of the stimulus. Pacing of the left bundle branch is achieved by advancing the lead into the right ventricle and screwing it deep into the interventricular septum. Due to the relatively large target area of the left bundle branch the success rate is very high (currently > 90%). Observational studies have shown a greater reduction in the QRS duration, a more pronounced improvement in systolic function and a lower hospitalization rate for heart failure associated with conduction system pacing compared to CRT using a coronary sinus lead. These findings have been confirmed in small randomized trials. Therefore, the use of left bundle branch pacing should be considered not only as a bail out in the case of failed resynchronization using coronary sinus lead placement but increasingly also as an initial pacing strategy. The results of the first large randomized trials are expected to be released in late 2024.

Variant patterns of electrical activation and recovery in normal human hearts revealed by noninvasive electrocardiographic imaging.

AIMS: Although electrical activity of the normal human heart is well characterized by the electrocardiogram, detailed insights into within-subject and between-subject variations of ventricular activation and recovery by noninvasive electroanatomic mapping are lacking. We characterized human epicardial activation and recovery within and between normal subjects using non-invasive electrocardiographic imaging (ECGI) as a basis to better understand pathology. METHODS AND RESULTS: Epicardial activation and recovery were assessed by ECGI in 22 normal subjects, 4 subjects with bundle branch block (BBB) and 4 with long-QT syndrome (LQTS). We compared characteristics between the ventricles [left ventricle (LV) and right ventricle (RV)], sexes, and age groups (<50/≥50years). Pearson's correlation coefficient (CC) was used for within-subject and between-subject comparisons. Age of normal subjects averaged 49 ± 14 years, 6/22 were male, and no structural/electrical heart disease was present. The average activation time was longer in LV than in RV, but not different by sex or age. Electrical recovery was similar for the ventricles, but started earlier and was on average shorter in males. Median CCs of between-subject comparisons of the ECG signals, activation, and recovery patterns were 0.61, 0.32, and 0.19, respectively. Within-subject beat-to-beat comparisons yielded higher CCs (0.98, 0.89, and 0.82, respectively). Activation and/or recovery patterns of patients with BBB or LQTS contrasted significantly with those found in the normal population. CONCLUSION: Activation and recovery patterns vary profoundly between normal subjects, but are stable individually beat to beat, with a male preponderance to shorter recovery. Individual characterization by ECGI at baseline serves as reference to better understand the emergence, progression, and treatment of electrical heart disease.

[Conduction disorders after transcatheter aortic valve implantation: incidence, characteristics, and clinical management]. / I disturbi di conduzione dopo impianto transcatetere di protesi aortica: incidenza, caratteristiche e gestione clinica.

Transcatheter aortic valve implantation may be complicated by the development of conduction disturbances, including left bundle branch block and high-grade atrioventricular blocks, especially in patients with predisposing risk factors, such as pre-existing right bundle branch block. Permanent pacemaker implantation is a procedure with potential short- and long-term complications, and it should be reserved to patients with appropriate indications. Electrophysiological testing and/or prolonged ambulatory ECG monitoring are valuable tools for stratifying the risk of pacemaker implantation. However, the management of new-onset conduction disorders is not always straightforward, and there are different approaches depending on the center's attitude. Therefore, the purpose of this review is to define clinical management based on current evidence, while awaiting data from randomized trials.

[Life insurance after percutaneous revascularization in a patient with severe left ventricular dysfunction and left bundle branch block: benefit of revascularization in the post-REVIVED-BCIS2 era]. / Un'assicurazione sulla vita dopo rivascolarizzazione percutanea in un paziente con severa disfunzione ventricolare sinistra e blocco di branca sinistro: beneficio della rivascolarizzazione coronarica nell'era post-REVIVED-BCIS2.

The recent results of the REVIVED-BCIS2 randomized clinical trial added further controversy on the utility of myocardial revascularization in patients with chronic coronary syndrome with reduced ejection fraction. However, coronary artery disease still represents the leading cause of heart failure with reduced ejection fraction, with the potential for functional recovery following complete revascularization due to the restoration of the so-called hibernating myocardium. We report an emblematic case of a patient with recovery of contractile function and normalization of the left bundle branch block after percutaneous coronary intervention of the right coronary artery chronic total occlusion.