Left Ventricular Septal Pacing Research Articles

Comparisons of long-term clinical outcomes with left bundle branch pacing, left ventricular septal pacing, and biventricular pacing for cardiac resynchronization therapy

BackgroundLeft bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) are referred to as left bundle branch area pacing. ObjectiveThis study investigated whether long-term clinical outcomes differ in patients undergoing LBBP, LVSP, and biventricular pacing (BiVP) for cardiac resynchronization therapy (CRT). MethodsConsecutive patients with reduced left ventricular ejection fraction (LVEF <50%) undergoing CRT were prospectively enrolled if they underwent successful LBBP, LVSP, or BiVP. The primary composite end point was all-cause mortality or heart failure hospitalization. Secondary end points included all-cause mortality, heart failure hospitalization, and echocardiographic measures of reverse remodeling. ResultsA total of 259 patients (68 LBBP, 38 LVSP, and 153 BiVP) were observed for a mean duration of 28.8 ± 15.8 months. LBBP was associated with a significantly reduced risk of the primary end point by 78% compared with both BiVP (7.4% vs 41.2%; adjusted hazard ratio [aHR], 0.22 [0.08–0.57]; P = .002) and LVSP (7.4% vs 47.4%; aHR, 0.22 [0.08–0.63]; P = .004]. The adjusted risk of all-cause mortality was significantly higher in LVSP than in BiVP (31.6% vs 7.2%; aHR, 3.19 [1.38–7.39]; P = .007) but comparable between LBBP and BiVP (2.9% vs 7.2%; aHR, 0.33 [0.07–1.52], P = .155). Propensity score adjustment also obtained similar results. LBBP showed a higher rate of echocardiographic response (ΔLVEF ≥10%: 60.0% vs 36.2% vs 16.1%; P < .001) than BiVP or LVSP. ConclusionLBBP yielded long-term clinical outcomes superior to those of BiVP and LVSP. The role of LVSP for CRT needs to be reevaluated because of its high mortality risk.

Ultra-High-Frequency ECG in Cardiac Pacing and Cardiac Resynchronization Therapy: From Technical Concept to Clinical Application.

Identifying electrical dyssynchrony is crucial for cardiac pacing and cardiac resynchronization therapy (CRT). The ultra-high-frequency electrocardiography (UHF-ECG) technique allows instantaneous dyssynchrony analyses with real-time visualization. This review explores the physiological background of higher frequencies in ventricular conduction and the translational evolution of UHF-ECG in cardiac pacing and CRT. Although high-frequency components were studied half a century ago, their exploration in the dyssynchrony context is rare. UHF-ECG records ECG signals from eight precordial leads over multiple beats in time. After initial conceptual studies, the implementation of an instant visualization of ventricular activation led to clinical implementation with minimal patient burden. UHF-ECG aids patient selection in biventricular CRT and evaluates ventricular activation during various forms of conduction system pacing (CSP). UHF-ECG ventricular electrical dyssynchrony has been associated with clinical outcomes in a large retrospective CRT cohort and has been used to study the electrophysiological differences between CSP methods, including His bundle pacing, left bundle branch (area) pacing, left ventricular septal pacing and conventional biventricular pacing. UHF-ECG can potentially be used to determine a tailored resynchronization approach (CRT through biventricular pacing or CSP) based on the electrical substrate (true LBBB vs. non-specified intraventricular conduction delay with more distal left ventricular conduction disease), for the optimization of CRT and holds promise beyond CRT for the risk stratification of ventricular arrhythmias.

Left Bundle Branch Pacing vs Left Ventricular Septal Pacing vs Biventricular Pacing for Cardiac Resynchronization Therapy

BackgroundLeft bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) are considered to be acceptable as LBBAP strategies. Differences in clinical outcomes between LBBP and LVSP are yet to be determined. ObjectivesThe purpose of this study was to compare the outcomes of LBBP vs LVSP vs BIVP for CRT. MethodsIn this prospective multicenter observational study, LBBP was compared with LVSP and BIVP in patients undergoing CRT. The primary composite outcome was freedom from heart failure (HF)–related hospitalization and all-cause mortality. Secondary outcomes included individual components of the primary outcome, postprocedural NYHA functional class, and electrocardiographic and echocardiographic parameters. ResultsA total of 415 patients were included (LBBP: n = 141; LVSP: n = 31; BIVP: n = 243), with a median follow-up of 399 days (Q1-Q3: 249.5-554.8 days). Freedom from the primary composite outcomes was 76.6% in the LBBP group and 48.4% in the LVSP group (HR: 1.37; 95% CI: 1.143-1.649; P = 0.001), driven by a 31.4% absolute increase in freedom from HF-related hospitalizations (83% vs 51.6%; HR: 3.55; 95% CI: 1.856-6.791; P < 0.001) without differences in all-cause mortality. LBBP was also associated with a higher freedom from the primary composite outcome compared with BIVP (HR: 1.43; 95% CI: 1.175-1.730; P < 0.001), with no difference between LVSP and BIVP. ConclusionsIn patients undergoing CRT, LBBP was associated with improved outcomes compared with LVSP and BIVP, while outcomes between BIVP and LVSP are similar.

Left bundle branch pacing versus left ventricular septal pacing as a primary procedural endpoint during left bundle branch area pacing: Evaluation of two different implant strategies.

Implant procedure features and clinical implications of left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) have not been yet fully described. We sought to compare two different left bundle branch area pacing (LBBAP) implant strategies: the first one accepting LVSP as a procedural endpoint and the second one aiming at achieving LBBP in every patient in spite of evidence of previous LVSP criteria. LVSP was accepted as a procedural endpoint in 162 consecutive patients (LVSP strategy group). In a second phase, LBBP was attempted in every patient in spite of achieving previous LVSP criteria (n = 161, LBBP strategy group). Baseline patient characteristics, implant procedure, and follow-up data were compared. The final capture pattern was LBBP in 71.4% and LVSP in 24.2% in the LBBP strategy group compared to 42.7% and 50%, respectively, in the LVSP strategy group. One hundred and eighty-four patients (57%) had proven LBB capture criteria with a significantly shorter paced QRS duration than the 120 patients (37%) with LVSP criteria (115 ± 9 vs. 121 ± 13 ms, p < .001). Implant parameters were comparable between the two strategies but the LBBP strategy resulted in a higher rate of acute septal perforation (11.8% vs. 4.9%, p = .026) without any clinical sequelae. Patients with CRT indications significantly improved left ventricular ejection fraction (LVEF) during follow-up irrespective of the capture pattern (from 35 ± 11% to 45 ± 14% in proven LBBP, p = .024; and from 39 ± 13% to 47 ± 12% for LVSP, p = .003). The presence of structural heart disease and baseline LBBB independently predicted unsuccessful LBB capture. The LBBP strategy was associated with comparable implant parameters than the LVSP strategy but resulted in higher rates of septal perforation. Proven LBB capture and LVSP showed comparable effects on LVEF during follow-up.

An individualized criterion for left bundle branch capture in patients with a narrow QRS complex

BackgroundLeft bundle branch (LBB) pacing (LBBP) is a physiological pacing; however, the accuracy of current electrocardiographic criteria for LBBP remains inadequate. ObjectiveThe purpose of this study was to establish a novel individualized criterion to improve the accuracy of LBBP determination in patients with a narrow QRS complex. MethodsPatients in whom both LBBP and left ventricular septal pacing (LVSP) were acquired during operation were enrolled. LBB conduction time (LBBCT) was measured from LBB potential (LBBpo) to intrinsic QRS onset. LBBpo-V6RWPT, Native-V6RWPT, and Paced-V6RWPT were respectively measured from LBBpo, intrinsic QRS onset, and stimulus to R-wave peak in V6. ΔV6RWPT was the difference value between Paced-V6RWPT and Native-V6RWPT. The accuracy of ΔV6RWPT criterion for determining LBBP was evaluated. ResultsIn all 71 enrolled patients, ΔV6RWPT was <30 ms during LBBP (21.3 ± 4.6 ms; range 9.3–28.3 ms) but was >30 ms during LVSP (38.5 ± 4.6 ms; range 31.1–47.0 ms). The probability distribution of ΔV6RWPT was well separated between LBBP and LVSP. Sensitivity and specificity of the novel criterion of "ΔV6RWPT <30 ms" for determining LBBP both were 100%. However, the optimal cutoff value of Paced-V6RWPT for validation of LBBP was 64.2 ms, and sensitivity and specificity were 84.5% and 97.2%, respectively. Paced-V6RWPT during LBBP was equivalent to LBBpo-V6RWPT in all patients. There was a strong linear correlation between Native-V6RWPT and LBBpo-V6RWPT (r = 0.796; P <.001). ConclusionΔV6RWPT could be an accurate individualized criterion for determining LBB capture with high sensitivity and specificity and was superior over the fixed Paced-V6RWPT criterion.

Difference of ventricular synchrony between LBBP, LBFP and LVSP: A speckle tracking echocardiographic study.

Left bundle branch area pacing (LBBAP) has emerged as a physiological and stable form of pacing. We aim to compare the mechanical ventricular synchrony of LBBP, LBFP, and LVSP. Proximal Left bundle branch pacing (LBBP), left bundle fascicular pacing (LBFP) and left ventricular septal pacing (LVSP) were identified in patients with bradycardia who successfully underwent LBBAP. Patients with left ventricular ejection fraction (LVEF) < 50% or QRS duration (QRSd) ≥ 120ms were excluded. By using electrocardiograms, the left ventricular activation time (LVAT) and QRS duration (QRSd) were measured to examine electrophysiological synchrony. As indications of mechanical synchrony, global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS), and peak strain dispersion (PSD) were evaluated by using 2-dimensional speckle tracking echocardiography (2D-STE). In 56 patients, data were collected during LBBP (n = 18), LBFP (n = 16), and LVSP (n = 22). LVSP resulted in a longer LVAT (91.3 ± 14.9ms) than LBBP (77.1 ± 10.8ms, P < 0.05) and LBFP (72.1 ± 9.6ms, P < 0.05), but all three groups had similar QRSd. There were no differences in GLS, GCS, GRS, or PSD between LBBP, LBFP, and LVSP. In patients with normal cardiac function and narrow QRS, though LBBAP with LBB capture resulted in better electrophysiological synchrony than without, the mechanical synchrony of the three groups was comparable.

Diverse QRS morphology reflecting variations in lead placement for left bundle branch area pacing.

Left bundle branch area pacing (LBBAP) is a potential alternative to His bundle pacing. This study aimed to investigate the impact of different septal locations of pacing leads on the diversity of QRS morphology during non-selective LBBAP. Non-selective LBBAP and left ventricular septal pacing (LVSP) were achieved in 50 and 21 patients with atrioventricular block, respectively. The electrophysiological properties of LBBAP and their relationship with the lead location were investigated. QRS morphology and axis showed broad variations during LBBAP. Echocardiography demonstrated a widespread distribution of LBBAP leads in the septum. During non-selective LBBAP, the qR-wave in lead V1 indicated that the primary location for pacing lead was the inferior septum (93%). The non-selective LBBAP lead was deployed deeper than the LVSP lead in the inferior septum. The Qr-wave in lead V1 with the inferior axis in aVF suggested pacing lead placement in the anterior septum. The penetration depth of the non-selective LBBAP lead in the anterior septum was significantly shallower than that in the inferior septum (72 ± 11 and 87 ± 8%, respectively). In lead V6, the deep S-wave indicated the time lag between the R-wave peak and the latest ventricular activation in the coronary sinus trunk, with pacemaker leads deployed closer to the left ventricular apex. Different QRS morphologies and axes were linked to the location of the non-selective LBBAP lead in the septum. Various lead deployments are feasible for LBBAP, allowing diversity in the conduction system capture in patients with atrioventricular block.

Redefining QRS transition to confirm left bundle branch capture during left bundle branch area pacing.

QRS transition criteria during dynamic manoeuvers are the gold-standard for non-invasive confirmation of left bundle branch (LBB) capture, but they are seen in <50% of LBB area pacing (LBBAP) procedures. We hypothesized that transition from left ventricular septal pacing (LVSP) to LBB pacing (LBBP), when observed during lead penetration into the deep interventricular septum (IVS) with interrupted pacemapping, can suggest LBB capture. QRS transition during lead screwing-in was defined as shortening of paced V6-R wave peak time (RWPT) by ≥10 ms from LVSP to non-selective LBBP (ns-LBBP) obtained during mid to deep septal lead progression at the same target area, between two consecutive pacing manoeuvres. ECG-based criteria were used to compared LVSP and ns-LBBP morphologies obtained by interrupted pacemapping. Sixty patients with demonstrated transition from LVSP to ns-LBBP during dynamic manoeuvers were compared to 44 patients with the same transition during lead screwing-in. Average shortening in paced V6-RWPT was similar among study groups (17.3 ± 6.8 ms vs. 18.8 ± 4.9 ms for transition during dynamic manoeuvres and lead screwing-in, respectively; p = 0.719). Paced V6-RWPT and aVL-RWPT, V6-V1 interpeak interval and the recently described LBBP score, were also similar for ns-LBBP morphologies in both groups. LVSP morphologies showed longer V6-RWPT and aVL-RWPT, shorter V6-V1 interpeak interval and lower LBBP score punctuation, without differences among the two QRS transition groups. V6-RWPT < 75 ms or V6-V1 interpeak interval > 44 ms criterion was more frequently achieved in ns-LBBP morphologies obtained during lead screwing-in compared to those obtained during dynamic manoeuvres (70.5% vs. 50%, respectively p = 0.036). During LBBAP procedure, QRS transition from LVSP to ns-LBBP can be observed as the lead penetrates deep into the IVS with interrupted pacemapping. Shortening of at least 10 ms in paced V6-RWPT may serve as marker of LBB capture.

Comparison of novel ventricular pacing strategies using an electro-mechanical simulation platform.

Focus of pacemaker therapy is shifting from right ventricular (RV) apex pacing (RVAP) and biventricular pacing (BiVP) to conduction system pacing. Direct comparison between the different pacing modalities and their consequences to cardiac pump function is difficult, due to the practical implications and confounding variables. Computational modelling and simulation provide the opportunity to compare electrical, mechanical, and haemodynamic consequences in the same virtual heart. Using the same single cardiac geometry, electrical activation maps following the different pacing strategies were calculated using an Eikonal model on a three-dimensional geometry, which were then used as input for a lumped mechanical and haemodynamic model (CircAdapt). We then compared simulated strain, regional myocardial work, and haemodynamic function for each pacing strategy. Selective His-bundle pacing (HBP) best replicated physiological electrical activation and led to the most homogeneous mechanical behaviour. Selective left bundle branch (LBB) pacing led to good left ventricular (LV) function but significantly increased RV load. RV activation times were reduced in non-selective LBB pacing (nsLBBP), reducing RV load but increasing heterogeneity in LV contraction. LV septal pacing led to a slower LV and more heterogeneous LV activation than nsLBBP, while RV activation was similar. BiVP led to a synchronous LV-RV, but resulted in a heterogeneous contraction. RVAP led to the slowest and most heterogeneous contraction. Haemodynamic differences were small compared to differences in local wall behaviour. Using a computational modelling framework, we investigated the mechanical and haemodynamic outcome of the prevailing pacing strategies in hearts with normal electrical and mechanical function. For this class of patients, nsLBBP was the best compromise between LV and RV function if HBP is not possible.

Electrophysiologic effects of left bundle branch area pacing: comparing left ventricular septal pacing and left bundle branch pacing

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Medtronic Background Left bundle branch area pacing(LBBAP) has been introduced as a more physiological pacing alternative to anti-bradycardia pacing and as an alternative to biventricular pacing in cardiac resynchronization therapy (CRT). LBBAP is the common denominator of left ventricular septal pacing(LVSP) and left bundle branch pacing(LBBP). In LVSP, there is only capture of the myocardium on the left side of the interventricular septum, whereas in LBBP there is additional capture of the left bundle branch(LBB) and subsequent Purkinje fibers. Purpose To investigate the electrophysiological differences between LBBP and LVSP. Methods Patients with a permanent pacemaker indication due to bradycardia or heart failure according to current guidelines were included and underwent LBBAP implantation. At baseline and during implantation, electrical activation parameters were recorded pacing at different sites (Right ventricle, LVSP and LBBP), using the standard 12-lead ECG and the ECG BELT. Electrophysiologic measures included: QRS duration, QRSarea calculated from the vectorcardiogram after conversion from the ECG using the Kors matrix, and standard deviation of activation time(SDAT) measured through the ECG BELT. Both QRS area and SDAT are known markers of ventricular dyssynchrony. Results 28 patients (17 male), with an age of 67±7 yrs underwent LBBAP. 21(75%) had a pacing indication for bradycardia with a baseline narrow QRS and 7(25%) for heart failure with a baseline LBBB. In 17 patients (61%) LBB capture was achieved. The remaining patients were treated with LVSP. In patients with baseline narrow QRS, both LVSP and LBBP showed a significant increase in QRS duration(p&amp;lt;0.001, p&amp;lt;0.001 resp.), without a significant difference in QRS duration between LVSP and LBBP(fig. 1 A). There was no significant difference in SDAT between LVSP and LBBP compared to baseline narrow QRS, and a significant SDAT reduction in patients with underlying LBBB (p=0.005, p&amp;lt;0.001 resp.) Furthermore, there was no significant SDAT difference between LVSP and LBBP(fig. 1 B). LVSP showed a small but significant increase in QRSarea compared to baseline narrow QRS (p=0.011) where LBBP showed no difference compared to baseline narrow QRS. Compared to baseline LBBB both LVSP and LBBP showed a significant QRSarea reduction (p=0.003, p&amp;lt;0.001 resp.). Moreover, there was a small but significant reduction in QRSarea when LBBP was achieved over LVSP(p=0.044) (fig. 1 C). Conclusion LVSP and LBBP showed a similar effect on ventricular synchrony in terms of SDAT, with levels of synchrony comparable to normal physiologic activation. Left bundle branch capture resulted in a small, but significant improvement in QRSarea over LVSP. Fig. 1 Relative changes in QRS duration(A), SDAT (B) and QRS area (C) compared to baseline narrow QRS (bradypacing) and baseline heart failure with LBBB. *p&amp;lt;0.05 compared to baseline, **p&amp;lt;0.05 for bradypacing and heart failure with LBBB combined.

Acute procedural comparison between left bundle branch pacing and left ventricular septal pacing

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch area pacing (LBBAP) includes both left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP). The implant procedure characteristics of these two pacing modalities have not been yet fully described. We sought to compare 2 different LBBAP implant strategies: the first one accepting LVSP as a procedure endpoint and the second one aiming at achieving LBBP in every patient. Methods Consecutive patients undergoing LBBAP at our centre from January 2020 to October 2022 were included. After our initial LBBAP learning curve, LVSP was accepted as a procedure endpoint in the first 217 patients. Thereafter, LBBP was attempted in every patient with a maximum of 5 lead deployment attempts or &amp;gt; 30 minutes for lead implant even if LVSP had been previously achieved. Definition of LBBP or LVSP was established according to currently accepted criteria. Procedure characteristics including total procedure time, LBBAP lead implant time, radiation exposure parameters, electrical parameters and acute complications were evaluated. Results A total of 422 consecutive patients were included in the analysis (217 patients with LVSP as acceptable endpoint, and 205 patients with LBBP as final endpoint). Baseline characteristics of the patients are described in table 1. In the LVSP group, the final capture pattern was LVSP in 57.6% and LBBP in 29% whereas in the LBBP group the final capture pattern was LVSP in 19.5% and LBBP in 71.2%. Failure of LBBAP occurred in 13.4% of LVSP group and 9.3% of LBBP group. LBBAP lead position in the septum was basal in 12,5% of LVSP group vs. 23,9% of LBBP group and medium in 81.7% and 72%, respectively (Table 2). A discrete LB potential was identified in 21.2% of LVSP group patients and in 45.8% of LBBP patients, p&amp;lt;0.0001. The LBBP strategy was associated with significantly longer LBBAP lead implant time (19±11min vs. 17±10 min, p=0.05), higher number of lead deployment attempts (3.4±1.8 vs 2.9±1.9, p=0.004), higher number of lead turns (22.4±4.3 vs. 18.3±4,1, p&amp;lt;0,0001) and higher fluoroscopy time (13.2±9.5 min vs. 10.6±9.3 min, p=0.003). Incidence of septal perforation was comparable between the 2 groups (10.6% for LVSP group and 7.8% for LBBP group, p=0.4) but development of complete AV block during implant tended to be more frequent in LBBP group (3.9% vs. 1.4%, p=0.13). The final paced QRS width, measured from the pacing spike, was comparable between the 2 groups: 161±18 ms for LVSP group and 158±19 ms for LBBP group, p=0.2. Conclusions LBBP can be achieved in more than 70% of unselected patients with significantly prolonged procedure time, higher number of lead deployment attempts and higher radiation exposure. When LVSP is accepted as an outcome, LBBP can be achieved in up to 29% of cases. The final paced QRS duration is comparable between the two implant strategies. Any potential clinical benefit of LBBP over LVSP in the long-term remains to be proven.

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

Biventricular pacing (Biv) and left bundle branch area pacing (LBBAP) are methods of cardiac resynchronization therapy (CRT). Currently, little is known about how they differ in terms of ventricular activation. This study compared ventricular activation patterns in left bundle branch block (LBBB) heart failure patients using an ultra-high-frequency electrocardiography (UHF-ECG). This was a retrospective analysis including 80 CRT patients from two centres. UHF-ECG data were obtained during LBBB, LBBAP, and Biv. Left bundle branch area pacing patients were divided into non-selective left bundle branch pacing (NSLBBP) or left ventricular septal pacing (LVSP) and into groups with V6 R-wave peak times (V6RWPT) < 90 ms and ≥ 90 ms. Calculated parameters were: e-DYS (time difference between the first and last activation in V1-V8 leads) and Vdmean (average of V1-V8 local depolarization durations). In LBBB patients (n = 80) indicated for CRT, spontaneous rhythms were compared with Biv (39) and LBBAP rhythms (64). Although both Biv and LBBAP significantly reduced QRS duration (QRSd) compared with LBBB (from 172 to 148 and 152 ms, respectively, both P < 0.001), the difference between them was not significant (P = 0.2). Left bundle branch area pacing led to shorter e-DYS (24 ms) than Biv (33 ms; P = 0.008) and shorter Vdmean (53 vs. 59 ms; P = 0.003). No differences in QRSd, e-DYS, or Vdmean were found between NSLBBP, LVSP, and LBBAP with paced V6RWPTs < 90 and ≥ 90 ms. Both Biv CRT and LBBAP significantly reduce ventricular dyssynchrony in CRT patients with LBBB. Left bundle branch area pacing is associated with more physiological ventricular activation.

Acute performance of stylet driven leads for left bundle branch area pacing: a comparison with lumenless leads

Abstract Funding Acknowledgements Type of funding sources: None. Background Lumen-less leads (LLL) and stylet driven leads (SDL) are currently used for left bundle branch area pacing (LBBAP). We sought to evaluate the acute performance of SDL during LBBAP in comparison with LLL. Methods This is an observational retrospective study including consecutive patients undergoing LBBAP at our institution.Acute lead performance was evaluated including implant success rate,electrical parameters,ECG characteristics and lead related complications (intraprocedure LBBAP lead dislodgment after having being penetrated into the septum in an stable position needing lead repositioning, septal perforation, coronary venous fistula, development of complete AV block not previously present and LBBAP lead damage during implant).Conduction system capture criteria were assessed before patient discharge during asynchronous ventricular pacing. Ventricular lead position within the septum was evaluated using paced QRS axis, fluoroscopic orthogonal views and post-procedure TTE, and classified as basal,mid or apical septum. Results 451 consecutive LBBAP implants were included, 333 using LLL and 118 using SDL. LBBAP acute success was significantly higher with LLL (91.6% for LLL vs 79.7% for SDL,p=0.001).Among patients with successful LBBAP,LBB capture criteria were achieved in 53.2% for LLL vs 36.4% for SDL,while left ventricular septal pacing (LVSP) was achieved in 39% vs 44.1%,respectively (p&amp;lt;0.0001). A basal lead position was more frequently obtained with LLL (19.8% for LLL vs 13.3% for SDL),while SDL were more frequently located at mid to apical septal positions (86.7% for SDL vs 80.1% for LLL, p=0.003).Paced ECG axis was inferior in 43.9% of LLL vs 28.9% of SDL and superior in 24.5% vs 42.1%, respectively,p=0.001.Intraprocedure lead dislodgment occurred in 9.3% of SDL vs 2.1% of LLL,p=0.001.In 5 cases of SDL (4.2%),lead damage occurred during lead implant needing lead replacement due to helix entrapment or malfunction with no such cases registered among LLL patients.Acute LBBAP lead-related complications were significantly higher for SDL vs LLL (29.1% vs 12.6%, respectively, p&amp;lt;0.0001,table 1),none of them needing additional interventions.Among patients with LBBAP criteria at the end of the procedure,34 (7.5%) experienced loss of r prime wave in V1 with paced QRS widening before hospital discharge,more frequently in patients with SDL (17.8% vs. 9.4%, respectively,p&amp;lt;0.0001) indicative of lead microdislodgment. Conclusions In our experience,acute lead performance is different between LLL and SDL.LBBAP implant success rate is significantly higher with LLL with higher percentage of patients with LBB capture criteria in comparison with SDL.SDL are associated with a more mid to apical and inferior lead position in the septum.A significantly higher rate of lead related complications during the implant procedure as well as higher rates of acute microdislodgment after implantation were also seen in SDL,none of them needing acute re-intervention.

Repolarization changes following conduction system pacing evaluated by ultra-high-frequency electrocardiography

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): This work was supported by the National Institute for Research of Metabolic and Cardiovascular Diseases project (Programme EXCELES, ID Project No. LX22NPO5104) — Funded by the European Union — Next Generation EU and a personal grant from the Dutch Heart Foundation (2021T016). Background On the surface electrogram (ECG) of a normal heart, the polarity of the T-wave is concordant with the QRS complex. This phenomenon could be explained by the presumption that regions that depolarize first repolarize last. Acute changes in ventricular activation can lead to abnormal T-waves. Conduction system pacing (CSP) leads to a more physiological ventricular activation compared to conventional right ventricular pacing (RVP), but little is known about repolarization changes following CSP. Purpose To compare repolarization changes following CSP with those during RVP and normal intrinsic activation in patients requiring bradycardia treatment. Methods Ultra-high-frequency electrocardiographic (UHF-ECG) measurements were acquired at time of implantation during normal intrinsic rhythm (narrow QRS [nQRS], n=199), selective His bundle pacing (sHBP, n=50), left ventricular septal pacing (LVsp, n=87), non-selective left bundle branch pacing (nsLBBP, n=47), and RVP (n=102). Activation and repolarization times were calculated for leads V1 and V6 from the time position of the QRS negative and from the T-wave positive derivative maxima respectively. Dyssynchrony (e-DYS) was defined as the time difference between leads V6 and V1. Differences between e-DYS depolarization (e-DYS-dpt) and repolarization (e-DYS-rpt) was evaluated by Kruskal Wallis tests. Results The left panel of Figure 1 demonstrates that during both nQRS and sHBP, e-DYS-dpt is small and slightly positive, while e-DYS-rpt is negative. RVP leads to a positive and increased e-DYS-dpt and e-DYS-rpt. LVsp and nsLBBP create negative e-DYS-dpt and e-DYS-rpt values. e-DYS-dpt and e-DYS-rpt was significant different between the groups (p-values &amp;lt;0.001). The middle and right panel of Figure 1 shows that during nQRS and sHBP, the activation-repolarization relationship is negative (~ first depolarized regions repolarize last). RVP, LVsp, and nsLBBP leads to a positive activation-repolarization relationship (~ first depolarized regions repolarize first). Conclusion sHBP preserves the physiological negative activation-repolarization relationship. RVP, LVsp, and nsLBBP reverses the activation-repolarization relationship, though smallest changes are present during LVsp. LVsp (after nQRS and sHBP) leads to the most synchronous activation and repolarization of the three.

Acute success, stability and safety of left bundle branch area pacing with steerable catheter and stylet-driven leads: A single center experience

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Right ventricular apical pacing is associated with adverse outcomes and there is an increasing preference to perform conduction system pacing as it allows for more physiological left ventricular activation. His-bundle pacing is known to be technically challenging and results in higher pacing thresholds and increased rates of lead dislodgement. Left bundle branch area pacing (LBBAP) is an emerging alternative form of conduction system pacing. Purpose We aim to study the acute success rates, short-term stability and safety using steerable catheter and stylet-driven (SD) leads for the purpose of LBBAP. Methods 40 consecutive patients who underwent LBBAP with steerable catheter and SD leads in our center from August 2021 to November 2022 were included in this series. Patients’ demographics, pacing indications, baseline QRS morphologies and duration and left ventricular ejection fraction (LVEF) were analysed. Acute success was defined as achieving stimulation to LV activation time (Stim-LVAT) ≤75ms or incomplete right bundle branch paced morphology in V1 [1, 2]. We also reported any left bundle branch (LBB) potential (if present) and the V6-V1 interpeak interval. All lead parameters and complications in the immediate (1 day) and short-term (1 week and 3-6 months) timeframe were evaluated. Results 40 patients' age (mean 72.75), gender (male 52.5%), body mass index (mean 24.15) and LVEF (mean 52.75%) were analysed. Pacing indications included sinus nodal dysfunction (25%), atrioventricular block (70%), heart failure with failed cardiac resynchronisation therapy (CRT) (2.5%) and atrial fibrillation (AF) requiring atrioventricular node ablation (2.5%). We achieved an acute success rate of 87.5% (5% with left ventricular septal pacing, 5% converted to conventional right ventricular septal pacing, and 2.5% converted to CRT). Reasons for failure to achieve successful LBBAP include persistent left superior vena cava, high pacing thresholds or inability to burrow lead into the septum for acceptable V1 morphology and Stim-LVAT due to resistance encountered during turning of the lead. 51.43% patients of the successful LBBAP patients had LBB potential present and/or interpeak interval &amp;gt;33ms [3]. Immediate and short-term lead parameters were stable and acceptable in all cases. There were no complications (such as lead dislodgement, rise in lead impedance or threshold) reported during the acute and short-term follow-up. Conclusion LBBAP is successful in 87.5% of our cases with use of steerable catheter deploying stylet-driven leads and is proven to be a safe and feasible method for conduction system pacing. Incremental experience with the delivery tools will further improve successful implantation. Longer term follow-up of these patients is needed to determine the long-term safety and stability of LBBAP using steerable catheter and stylet-driven leads.

A diagnostic dilemma of left bundle branch pacing.

Journal of Cardiovascular ElectrophysiologyVolume 34, Issue 6 p. 1491-1494 DEVICE ROUNDS A diagnostic dilemma of left bundle branch pacing Yoji Iida MD, Corresponding Author Yoji Iida MD [email protected] orcid.org/0000-0002-2002-9295 Department of Cardiology, Kobari General Hospital, Chiba, Japan Correspondence Yoji Iida, MD, Department of Cardiology, Kobari General Hospital, 29-1, Yokouchi, Noda, Chiba, 278-8501, Japan. Email: [email protected]Search for more papers by this author Yoji Iida MD, Corresponding Author Yoji Iida MD [email protected] orcid.org/0000-0002-2002-9295 Department of Cardiology, Kobari General Hospital, Chiba, Japan Correspondence Yoji Iida, MD, Department of Cardiology, Kobari General Hospital, 29-1, Yokouchi, Noda, Chiba, 278-8501, Japan. Email: [email protected]Search for more papers by this author First published: 07 May 2023 https://doi.org/10.1111/jce.15921 Disclosures: None. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL REFERENCES 1Wu S, Chen X, Wang S, et al. Evaluation of the criteria to distinguish left bundle branch pacing from left ventricular septal pacing. JACC Clin Electrophysiol. 2021; 7: 1166- 1177. 2Jastrzębski M, Kiełbasa G, Curila K, et al. Physiology-based electrocardiographic criteria for left bundle branch capture. Heart Rhythm. 2021; 18: 935- 943. 3Jastrzębski M, Burri H, Kiełbasa G, et al. The V6-V1 interpeak interval: a novel criterion for the diagnosis of left bundle branch capture. Europace. 2022; 24: 40- 47. Volume34, Issue6June 2023Pages 1491-1494 ReferencesRelatedInformation

Approach to Left Bundle Branch Pacing.

Cardiac pacing refers to the implantation tool serving as a treatment modality for various indications, the most common of which is symptomatic bradyarrhythmia. Left bundle branch pacing has been noted in the literature to be safer than biventricular pacing or His-bundle pacing in patients with left bundle branch block (LBBB) and heart failure, thereby becoming the focus of further research on cardiac pacing. A review of the literature was conducted using a combination of keywords, including "Left Bundle Branch Block," "Procedural techniques," "Left Bundle Capture," and "Complications." The following factors have been investigated as key criteria for direct capture: paced QRS morphology, peak left ventricular activation time, left bundle potential, nonselective and selective left bundle capture, and programmed deep septal stimulation protocol. In addition, complications of LBBP, inclusive of septal perforation, thromboembolism, right bundle branch injury, septal artery injury, lead dislodgement, lead fracture, and lead extraction, have also been elaborated on. Despite clinical implications based on clinical research comparing the use of LBBP with other forms such as right ventricular apex pacing, His-bundle pacing, biventricular pacing, and left ventricular septal pacing, a paucity in the literature on long-term effects and efficacy has been noted. LBBP can thus be considered to have a promising future in patients requiring cardiac pacing, assuming that additional research on clinical outcomes and the limitation of significant complications such as thromboembolism can be established.

My preferred approach to left bundle branch area pacing: Stylet-driven leads.

Left bundle branch area pacing (LBBAP) is emerging as an attractive pacing modality as it offers more physiologic pacing compared to standard right ventricular apical pacing and is associated with excellent pacing characteristics compared to His bundle pacing (HBP) 1-5. Left ventricular septal pacing (LVSP) via a transseptal route was first reported by Mafi rad in 2017 using a custom made pacing lead, a modification of the lumenless Select Secure model 3830 (Medtronic Inc), but with a prolonged helix of 4 mm1.

A Continuous Pacing and Recording Technique for Differentiating Left Bundle Branch Pacing From Left Ventricular Septal Pacing: Electrophysiologic Evidence From an Intrapatient-Controlled Study.

Left bundle branch pacing (LBBP) is a promising approach for achieving near-physiologic pacing. However, differentiating LBBP from left ventricular septal endocardial pacing (LVS(e)P) remains a challenge. This study aimed to establish a simple and effective method for differentiating LBBP from LVS(e)P and to evaluate their electrophysiologic characteristics. LBBP, using continuous uninterrupted pacing and real-time monitoring of electrocardiograms along with intracardiac electrograms, was performed in 97 consecutive patients. We evaluated the electrophysiologic characteristics observed during LBBP using 6 modalities: right ventricular septal pacing (RVSP), intraventricular septal pacing (IVSP 1 and 2), LVS(e)P, nonselective LBBP (NSLBBP), and selective LBBP (SLBBP). Of the 97 patients, 87 (89.7%) met the criteria (abrupt change in paced QRS morphology with a transition from Qr to QR/qR in lead V1 and shortening of stimulus to V6 R-wave peak time [Stim-V6RWPT] of ≥ 10 ms with constant output while rather than after lead screwing) for nonselective left bundle branch (LBB) capture. Selective LBB capture was observed in 82 patients (84.5%). The Stim-V6RWPT of NSLBBP and SLBBP were significantly shorter than LVS(e)P (respectively, 67.1 ± 8.7 ms, 67.0 ± 9.3 ms, and 82.1 ± 10.9 ms). Stim-QRSend was the narrowest in IVSP2 (136.6 ± 15.2 ms) instead of NSLBBP (140.0 ± 17.1 ms). The uninterrupted pacing technique for differentiating LBBP from LVS(e)P in the same group of patients is feasible. Electrophysiologic evidence from our intrapatient-controlled study shows that LBBP and LVS(e)P differ in ventricular electrical synchronization.

Bilateral septal pacing in combination with coronary venous pacing for cardiac resynchronization therapy.

Conventional right ventricular pacing combined with coronary venous pacing (CVP) is a mainstay for cardiac resynchronization therapy (CRT). However, QRS duration of conventional CRT may be frequently more than 130ms. This study aimed to evaluate the effectiveness of QRS narrowing by bilateral septal pacing (BSP) in combination with CVP for CRT (BSP-CRT). Fourteen patients with QRS>130ms of conventional CRT after failure of physiological conduction system pacing were enrolled. Electrophysiologic characteristics were compared among different modes of CRT during procedure. BSP which was defined as capture of both sides of interventricular septum manifested as shortened R wave peak time without a right bundle branch block QRS pattern. BSP-CRT were successfully achieved in 85.7% (12/14) patients. QRS duration at baseline was 185±13ms and significantly narrowed to 156±9ms during conventional CRT (n=14, P<.001), to 143±7ms during left ventricular septal pacing (LVSP) in combination with CVP for CRT (LVSP-CRT) (n=9, P<.001), and further to 122±10ms during BSP-CRT (n=12, P<.001). Notably, among 7 patients in whom both LVSP and BSP were achieved, BSP-CRT outperformed LVSP-CRT at QRS narrowing by 16% (P<.001). At 3-month follow-up, left ventricular ejection fraction improved from 29±6% to 41±8% (P<.001). BSP-CRT resulted in superior acute electrical synchronization to conventional CRT and might be considered as an alternative to conventional CRT with QRS more than 130ms.