ICD electrode implantation for left bundle branch area pacing

Comparison of immediate changes of repolarization parameters after left bundle branch area pacing and traditional biventricular pacing in heart failure patients

Left bundle branch–optimized cardiac resynchronization therapy: Pursuing the optimal resynchronization in severe (distal) conduction system disease

Rescue left bundle branch area pacing in coronary venous lead failure or nonresponse to biventricular pacing: Results from International LBBAP Collaborative Study Group.

His-bundle pacing is the best approach to physiological pacing.

Background: Cardiac resynchronization therapy (CRT) using biventricular pacing (BVP) has limited efficacy in patients with heart failure (HF) and right bundle branch block (RBBB). Left bundle branch area pacing (LBBAP) has been reported as an alternative option for BVP-CRT. The aim of the study was to assess the feasibility and outcomes of LBBAP in patients with RBBB and indication for CRT in an international, multicenter, collaborative study. Methods: LBBAP was attempted in patients with LVEF<50%, RBBB and indications for CRT. Procedural, pacing and ECG parameters, clinical response (no HF hospitalization and improvement in NYHA class) and echocardiographic response (≥5% increase in ejection fraction) to LBBAP was assessed. Results: LBBAP was attempted in 121 patients and successful in 107 (88%). 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±0.3V@0.5ms and 10±9mV at implant and remained stable during mean follow-up of 13±8 months. LBBAP resulted in significant narrowing of QRS duration (156±20ms to 150±24ms (p=0.01) with R-wave peak times in V6 of 85±16ms. LVEF improved from 35±9 to 43±12%(p<0.01). Clinical and echocardiographic response was observed in 60% and 61% of patients, respectively. Female gender and reduction in QRS duration with LBBAP were predictive of echocardiographic response and super-response. Conclusions: LBBAP is a feasible and safe alternative to BVP to deliver CRT in patients with RBBB. LBBAP provides low and stable pacing thresholds with favorable clinical and echocardiographic response.

Left bundle branch area pacing compared with biventricular pacing for cardiac resynchronization therapy in patients with left ventricular ejection fraction ≤50%: Results from the International Collaborative LBBAP Study (I-CLAS).

Background Interest in conduction system pacing (CSP) has increased in recent years. For left bundle branch area pacing (LBBAP), 4F and 6F pacing leads have been shown to be effective and safe. No information is available on the potential use of ICD leads for LBBAP. Aim The objective of the study was to demonstrate the feasibility of implanting an ICD lead in the LBBAP position to reduce the number of leads for CRT-D therapy. Patients and Methods We implanted the 7F ICD lead in the LBBAP position through a new 10F CSP delivery sheath in ten consecutive patients. Periprocedural data, QRS morphology and degree of QRS reduction were analyzed. Results Ten consecutive patients (one female) aged 69.5±9.2 years were treated with the above-mentioned method. Eight patients had ischemic cardiomyopathy and two patients had nonischemic cardiomyopathy. All patients had a CRT-D indication. Eight patients had a wide QRS complex with complete LBB and a QRS complex of 184.8±25.8 ms. Two patients had a narrow QRS complex but first-degree AV block with a PR interval greater than 240 ms. Left ventricular ejection fraction was 31.8±8.6%. Operative and fluoroscopy times were 103.6±30.3 minutes and 10.5±6.1 minutes, respectively. On average, 1.7 ± 0.6 screwing attempts were required per patient. The intraprocedural LBBAP threshold was 0.78±0.6V/1.0ms, the impedance was 530.8±86.5 ohm, and the R-wave amplitude was 9±3.3mV. The unipolar paced QRS complex was 123.6±15.9ms, the bipolar paced QRS complex was 129.5±12.8ms, and the bipolar paced QRS complex on the next day was 133.3±11.7. The mean duration from stimulus to R-wave peak in lead V6 was 82.9 ± 19.7 ms. The R-wave interpeak interval between leads V6 and V1 was 43.4 ± 9.7 ms. All but one patient received an effective defibrillation threshold test at 30J (n=8) and 36J (n=1). One patient was not tested during the procedure due to high risk. Conclusion This first-in-human study of ICD lead implantation in the LBBAP position demonstrated its feasibility and efficacy in achieving conduction system stimulation. This approach may lead to a reduction in the number of leads implanted for cardiac resynchronization therapy. Figure 1. A- RAO view, angiography of the RV for verification of the TVA-summit. B- LAO view, angiography from the CSP- sheath after reaching final position of the LBBAP lead (right sided interventricular septum - yellow dotted line). C – 12 lead ECG (speed 50mm/sec) demonstrating paced and native QRS complexes. D – Fluoroscopy in RAO view, final result. E – Fluoroscopy in LAO view, final result. F – Transthoracic echocardiography the next day (4Ch view) demonstrates optimal LBBAP lead position.. RAO – right anterior oblique; LAO – left anterior oblique; TVA – tricuspid valve anulus; CSP – conduction system pacing; LBBAP – left bundle branch area pacing.Figure 1.

Left Bundle Branch Area Pacing for Cardiac Resynchronization Therapy: Results From the International LBBAP Collaborative StudyGroup.

Background Biventricular pacing (BVP) is recommended from the most recent ESC guidelines as the first line pacing strategy in patients with heart failure (HF) that require cardiac resynchronization therapy (CRT). (1) Many studies have shown its beneficial effects regarding morbidity and mortality in this population. (2, 3) However, 10% of patients cannot be treated by BVP due to unsuitable coronary sinus vein, while 30-40% are non-responders to BVP and experience no benefit from this treatment.(4) Left bundle branch area pacing (LBBAP) is a new pacing modality (5) that can achieve narrow QRS and improve left ventricular function in patients with HF, by engaging the intrinsic conduction pathway of the heart. Also, it appears to have better results in electrical and mechanical synchrony compared with BVP. Purpose We conducted a systematic review and meta-analysis to compare the two pacing modalities in terms of hard clinical outcomes, in patients with heart failure that require CRT. Methods Medline, Embase, Cochrane Central Register of Controlled Trials and Web of Science databases were systematically searched for studies comparing LBBAP with BVP for CRT in patients with HF. Outcomes of interest were all-cause mortality, Heart Failure Hospitalizations (HFH) and New York Heart Association (NYHA) class improvement. Two independent investigators identified studies, extracted data, and assessed the risk of bias using the Cochrane Risk of Bias 2 tool for randomized clinical trials and the Newcastle-Ottawa-Scale for observational studies. Pairwise meta-analysis was conducted using random and fixed effects models. Risk Ratios (RRs) and weighted mean difference (WMD) with 95% confidence intervals (CIs) were used to report dichotomous and continuous variables respectively. Heterogeneity was assessed with the I² statistic. Results In total, 764 studies were retrieved and finally 9 trials with 992 individuals (365 in LBBAP and 627 in BVP group) were included in the analysis. The mean follow-up duration was 13 ± 5.82 months and the average procedural success rate in the LBBAP group was 89.8%. The baseline characteristics were similar between the two groups. Pooled analysis showed that the two methods had no difference in terms of all-cause mortality (RR:0.87 CI 95%:0.38 to 2.02; I²=0%; p=0.750, Figure 1) with 8 (2.4%) vs 17 (2.9%) events occurring in LBBAP and BVP group respectively. However, LBBAP was found to have significantly lower risk for HFH (RR:0.58 CI 95%:0.38 to 0.91; I²=0%; p=0.020, Figure 2A) and to achieve more improvement in NYHA class compared with BVP (WMD: -0.40, CI 95%: -0.68 to -0.12; I²=72%; p=0.005; Figure 2B). Conclusions To the best of our knowledge this is the first meta-analysis that assesses exclusively the clinical outcomes of LBBAP compared to BVP in such an important number of patients. LBBAP presents better outcomes in HFH and NYHA class improvement, but it has no difference in all-cause mortality in comparison with BVP.Figure 1.All-cause mortalityFigure 2.A.HFH B.NYHA class improvement

Navik 3D (APN Health, Waukesha, WI, USA) is a navigation software program that uses two-dimensional (2D) fluoroscopy images to provide three-dimensional (3D) information. Left bundle branch area (LBBA) pacing (LBBAP) is a novel physiologic pacing technique where the lead is placed in the right ventricular (RV) basal septum to capture the left bundle branch (LBB). Precise lead placement in this region can be challenging using 2D fluoroscopy. We studied the feasibility of using Navik 3D to identify the location, plane, and depth of the lead in the septum to assist with LBBAP procedures. This observational, prospective single-center study included 14 patients undergoing LBBAP. Navik 3D was used to identify the LBBA, RV septum, RV apex, and lead position in three dimensions using two orthogonal 2D views. The 3D images were overlaid on real-time, gated fluoroscopic images for navigation of the lead. Images of the 3D locations and successful or unsuccessful lead locations were projected onto 2D fluoroscopic images, allowing for repositioning if necessary. All attempted patients had successful LBBA lead implants. An LBB potential was recorded in 61.5% of the patients. Selective LBBAP was achieved in 85% of the patients. The mean QRS duration postimplant was 129.8 ± 13.1 ms. The mean left ventricular activation time (stimulus R-wave peak in V6) postimplant was 75 ± 12 ms. No acute complications were recorded. 3D localization of the LBBA using the Navik 3D mapping system was feasible and may assist with more appropriate LBBA lead placement.

Left bundle branch area pacing (LBBAP) may be an alternative to biventricular pacing (BVP) for cardiac resynchronization therapy (CRT). We sought to compare the acute hemodynamic and ECG effects of LBBAP, BVP, and left bundle-optimized therapy CRT (LOT-CRT) in CRT candidates with advanced conduction disease. In this multicenter study, 48 patients with either nonspecific interventricular conduction delay (n=29) or left bundle branch block (n=19) underwent acute hemodynamic testing to determine the change in left ventricular pressure maximal first derivative (LV dP/dtmax) from baseline atrial pacing to BVP, LBBAP, or LOT-CRT. Atrioventricular-optimized increases in LV dP/dtmax for LOT-CRT (mean, 25.8% [95% CI, 20.9%-30.7%]) and BVP (26.4% [95% CI, 20.2%-32.6%]) were greater than unipolar LBBAP (19.3% [95% CI, 15.0%-23.7%]) or bipolar LBBAP (16.4% [95% CI, 12.7%-20.0%]; P≤0.005). QRS shortening was greater in LOT-CRT (29.5 [95% CI, 23.4-35.6] ms) than unipolar LBBAP (11.9 [95% CI, 6.1-17.7] ms), bipolar LBBAP (11.7 ms [95% CI, 6.4-17.0]), or BVP (18.5 [95% CI, 11.0-25.9] ms), all P≤0.005. Compared with patients with left bundle branch block, patients with interventricular conduction delay experienced less QRS reduction (P=0.026) but similar improvements in LV dP/dtmax (P=0.29). Bipolar LBBAP caused anodal capture in 54% of patients and resulted in less LV dP/dtmax improvement than unipolar LBBAP (18.6% versus 23.7%; P<0.001). Subclassification of LBBAP capture (European Heart Rhythm Association criteria) indicated LBBAP or LV septal pacing in 27 patients (56%) and deep septal pacing in 21 patients (44%). The hemodynamic benefit of adding left ventricular coronary vein pacing to LBBAP depended on baseline QRS duration (P=0.031) and success of LBBAP (P<0.004): LOT-CRT provided 14.5% (5.0%-24.1%) greater LV dP/dtmax improvement and 20.8 (12.8-28.8) ms greater QRS shortening than LBBAP in subjects with QRS ≥171 ms and deep septal pacing capture type. In a CRT cohort with advanced conduction disease, LOT-CRT and BVP provided greater acute hemodynamic benefit than LBBAP. Subjects with wider QRS or deep septal pacing are more likely to benefit from the addition of a left ventricular coronary vein lead to implement LOT-CRT. URL: https://www.clinicaltrials.gov; Unique identifier: NCT04905290.

Left bundle branch area pacing (LBBAP) has emerged as a physiological alternative pacing strategy to biventricular pacing (BIVP) in cardiac resynchronization therapy (CRT). We aimed to assess the impact of LBBAP vs. BIVP on all-cause mortality and heart failure (HF)-related hospitalization in patients undergoing CRT. Studies comparing LBBAP and BIVP for CRT in patients with HF with reduced left ventricular ejection fraction (LVEF) were included. The coprimary outcomes were all-cause mortality and HF-related hospitalization. Secondary outcomes included procedural and fluoroscopy time, change in QRS duration, and change in LVEF. Thirteen studies (12 observational and 1 RCT, n = 3239; LBBAP = 1338 and BIVP = 1901) with a mean follow-up duration of 25.8months were included. Compared to BIVP, LBBAP was associated with a significant absolute risk reduction of 3.2% in all-cause mortality (9.3% vs 12.5%, RR 0.7, 95% CI 0.57-0.86, p < 0.001) and an 8.2% reduction in HF-related hospitalization (11.3% vs 19.5%, RR 0.6, 95% CI 0.5-0.71, p < 0.00001). LBBAP also resulted in reductions in procedural time (mean weighted difference- 23.2min, 95% CI - 42.9 to - 3.6, p = 0.02) and fluoroscopy time (- 8.6min, 95% CI - 12.5 to - 4.7, p < 0.001) as well as a significant reduction in QRS duration (mean weighted difference:- 25.3ms, 95% CI - 30.9 to - 19.8, p < 0.00001) and a greater improvement in LVEF of 5.1% (95% CI 4.4-5.8, p < 0.001) compared to BIVP in the studies that reported these outcomes. In this meta-analysis, LBBAP was associated with a significant reduction in all-cause mortality as well as HF-related hospitalization when compared to BIVP. Additional data from large RCTs is warranted to corroborate these promising findings.

Left bundle branch area pacing results in more physiological ventricular activation than biventricular pacing in patients with left bundle branch block heart failure.

Background Cardiac Resynchronization Therapy (CRT) is the standard treatment for patients with dyssynchronous heart failure. Despite the effectiveness of conventional biventricular pacing (BiVP), 6-16% of patients develop ventricular tachyarrhythmias (VTAs) within a year of implantation. The relationship between BiVP and the development of VTAs is still under debate. During BiVP, the left-sided epicardium-to-endocardium activation creates a non-physiological activation and hence a non-physiological repolarization, which might trigger VTAs. A novel alternative treatment option to BiVP that on the contrary induces a left ventricular endocardium-to-epicardium activation, is left bundle branch area pacing (LBBAP). We hypothesized that LBBAP leads to a more homogenous repolarization than conventional BiVP. Purpose To compare time-dependent activation and repolarization changes in patients with dyssynchronous heart failure receiving LBBAP versus BiVP. Methods Patients eligible for CRT who underwent LBBAP (n=21) or BiVP (n=94) were retrospectively included. Standard 12-lead electrocardiograms obtained prior to implantation [baseline], shortly following implantation (0-2 days, [acute phase]), and after prolonged pacing during follow-up (31-180 days, [chronic phase]) were analyzed. QRS duration and QRS area were calculated through reconstruction of the vectorcardiogram and further analyzed together with corrected QT (QTc) and corrected Tpeak-Tend (Tp-e,c) intervals using a semi-automatic approach in MATLAB. Differences between LBBAP and BiVP patients were determined using the Mann-Whitney U-test. Time-dependent changes within groups were determined using the Wilcoxon signed-rank tests. Significance was defined as a p-value ≤0.05. Results (see figure): Compared to baseline, QRS duration and QRS area decreased significantly during the acute phase (both p &amp;lt; 0.01) and stabilized during chronic pacing for both BiVP and LBBAP patients. Differences in QRS duration or QRS area between LBBAP and BiVP were not significant at any of the time points. In the acute phase, BiVP resulted in a temporary and significant prolongation of both QTc and Tp-e,c compared to baseline (both p &amp;lt; 0.01). However, there was a subsequent shortening observed between the acute and chronic phases for both QTc and Tp-e,c (both p &amp;lt; 0.01). Compared to baseline, LBBAP acutely shortened Tp-e,c (p = 0.02) and tended to shorten QTc. During chronic pacing, LBBAP shortened QTc and Tp-e,c compared to baseline (p = 0.01 and p &amp;lt; 0.01). The decreases in QTc and Tp-e,c were larger in LBBAP than in BiVP patients in the acute and chronic pacing phase (all p &amp;lt;0.01). Conclusion CRT induces activation changes in both BiVP and LBBAP patients to a comparable extent. While BiVP leads to an acute increase in repolarization dispersions, LBBAP reduces markers of repolarization dispersion compared to baseline. The diminished dispersion of repolarization might contribute to an antiarrhythmic effect with LBBAP.

Introduction Left bundle branch area pacing (LBBAP) has become, in the last years, the preferred method for physiological pacing due to a wider target area, optimal pacing and sensing thresholds, and stable parameters over time. LBBAP ensures rapid and synchronous left ventricular (LV) activation through the left-sided conduction system. On the other hand, there is little data on right ventricular (RV) activation in LBBAP. The purpose of this study was to evaluate the impact of LBBAP on the right heart anatomy and function over a mid-term follow-up period. Material and methods All consecutive patients with successful LBBAP for bradyarrhythmic indications between February 2021 and July 2022 at our institution were eligible for this study. Left bundle branch capture was defined as a paced QRS complex of right bundle branch block morphology, and proof of transition from non-selective to selective capture with differential pacing maneuvers. To avoid confounders, patients with LV ejection fraction below 40% and with severe valvular disease were excluded. In the end, 57 patients were prospectively evaluated. Patient and procedural characteristics were recorded at baseline and follow-up. Also, right atrial (RA) volume, RV basal diameter, tricuspid annulus peak systolic elevation (TAPSE), RV S` wave (RVS`W), and tricuspid regurgitation (TR) were evaluated before the procedure and at the end of the follow-up period. Results The mean age of the patients was 68.9± 10 years, and 70% were males. 29.8% had a baseline right bundle branch block, and 22.8% had a left bundle branch block morphology. The baseline LV ejection fraction was 54.3 ± 9.9 %. The paced QRS duration was similar to the baseline values (128.5 ± 16.3 vs. 134.4 ± 30.4 msec, p=0.119). The pacing and sensing thresholds were 0.7 ± 0.3 V at 0.4 ms pulse duration and 9.7 ± 4.2 mV, respectively. The mean LV activation time (measured as the R wave peak time in V6) was 80.9 ± 12 msec, and the mean RV activation time (measured as the difference between QRS duration and LV activation time) was 51.9 ± 24.2 msec. The patients were followed over a mean period of 591.2 ± 150.3 days. There were no complications over the follow-up period that led to pacing interruption. The follow-up pacing (0.6 ± 0.2 V, p=0.003) and sensing (11.7 ± 6 mV, p= 0.023) thresholds showed significant improvement compared to the procedural values. The right heart echocardiographic evaluation showed non-statistically significant changes between the follow-up and the baseline values for RA volumes (57.9 ± 33.7 vs. 51.5 ± 28.4 ml, p=0.122), RV basal diameter (32.8 ± 5.4 vs. 31.8 ± 6.4 mm, p=0.31), RVS`W (12.8 ± 3.2 vs. 12.85 ± 2.7 cm/sec, p=0.933), and TR (1.8±0.8 vs. 2±1, p=0.07). On the other hand, there was a significant improvement in the TAPSE (22.2±4.3 vs. 20.7±3.6 mm, p=0.021). Conclusions LBBAP was associated with preserved dimensions and function of the right cardiac chambers over a medium-term follow-up period.