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

INTRODUCTION

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

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

Background

Lumenless leads (LLLs) are widely used for left bundle branch area pacing (LBBAP). Recently, stylet-driven leads (SDLs) have also been used for LBBAP.

Objective

The purpose of this study was to evaluate the acute performance of SDLs during LBBAP in comparison with LLLs.

Methods

Consecutive patients undergoing LBBAP for bradycardia or cardiac resynchronization therapy indications at 2 high-volume, early conduction system pacing adopters, tertiary centers were included from January 2019 to July 2023. Patients received either SDLs or LLLs at the discretion of the implanting physician. Acute performance and follow-up data of both lead types were evaluated.

Results

A total of 925 LBBAP implants were included, 655 using LLLs and 270 using SDLs. Overall, LBBAP acute success was significantly higher with LLLs than SDLs (95.3% vs 85.1%, respectively; P <.001) even after the learning curve (97% vs 86%; P = .013). LLLs were implanted in more mid-basal septal positions in comparison with SDLs, which tended to be implanted in more inferior and mid-apical septal positions. Acute lead-related complications were higher with SDLs than LLLs (15.9% vs 6.1%, respectively; P <.001) with 15 cases of lead damage during implant (4.4% vs 0.5%; P <.001) but decreased with acquired experience and were comparable in the last 100 patients included in each group. Lead implant and fluoroscopy times were shorter for SDLs, with lead dislodgment occurring in 0.9% with LLLs and 1.5% with SDLs (P = .489).

Conclusion

Acute lead performance proved to be different between LLLs and SDLs. A specific learning curve should be considered for SDLs even for implanters with extensive previous experience with LLLs.

Conduction System Pacing for Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) via biventricular pacing (BiVP-CRT) is considered a mainstay treatment for symptomatic heart failure patients with reduced ejection fraction and wide QRS. However, up to one-third of patients receiving BiVP-CRT are considered non-responders to the therapy. Multiple strategies have been proposed to maximize the percentage of CRT responders including two new physiological pacing modalities that have emerged in recent years: His bundle pacing (HBP) and left bundle branch area pacing (LBBAP). Both pacing techniques aim at restoring the normal electrical activation of the ventricles through the native conduction system in opposition to the cell-to-cell activation of conventional right ventricular myocardial pacing. Conduction system pacing (CSP), including both HBP and LBBAP, appears to be a promising pacing modality for delivering CRT and has proven to be safe and feasible in this particular setting. This article will review the current state of the art of CSP-based CRT, its limitations, and future directions.

Safety and feasibility of conduction system pacing in patients with congenital heart disease

INTRODUCTION

Conduction system pacing (CSP) has emerged as an ideal physiologic pacing strategy for patients with permanent pacing indications. We sought to evaluate the safety and feasibility of CSP in a consecutive series of unselected patients with congenital heart disease (CHD).

METHODS

Consecutive patients with CHD in which CSP was attempted were included. Safety and feasibility, implant tools and electrical parameters at implant and at follow-up were evaluated.

RESULTS

A total of 20 patients were included (10 with a previous device). A total of 10 patients had complex forms of CHD, 9 moderate defects and 1 a simple defect. CSP was achieved in 75% of cases (10 His bundle pacing, 5 left bundle branch pacing) with left ventricular septal pacing in the remaining 5 patients. Procedure times and fluoroscopy times were prolongued (126 ± 82 min and 27 ± 30 min, respectively). Ventricular lead implant times widely varied ranging from 4 to 115 min, (mean 31 ± 28 min) and the use of multiple delivery sheaths was frequent (50%). The QRS width was reduced from 145 ± 36 ms at baseline to 116 ± 18 ms with CSP. Implant electrical parameters included: CSP pacing threshold 0.95 ± 0.65 V; R wave amplitude 9.2 ± 8.8 mV and pacing impedance 632 ± 183 Ohms, and remained stable at a median follow-up of 478 days (interquartile range: 225-567). Systemic ventricle systolic function and NYHA class (1.50 ± 0.51 vs. 1.10 ± 0.31; p = .008) significantly improved at follow-up. Lead revision was required in one patient at Day 4.

CONCLUSIONS

Permanent CSP is safe and feasible in patients with CHD although implant technique is complex.

Clinical recurrence of palpitations following slow pathway ablation in patients with suspected paroxysmal supraventricular tachycardias but non-documented, non-inducible tachycardias

Funding Acknowledgements

Type of funding sources: None.

Introduction

Catheter ablation is recommended as first-line treatment in patients with atrioventricular nodal reentry tachycardias (AVNRT). However, the best therapeutic modality in patients with dual AV nodal physiology but non-inducible tachycardias in electrophysiological study (EPS) remains controversial, especially when no tachycardias have been documented.

Our objective was to evaluate the results of empirical slow pathway ablation in patients showing dual AV nodal physiology but non-inducible AVNRT.

Methods

Multicenter, retrospective, observational registry of consecutive patients undergoing EPS due to clinical suspicion of paroxysmal supraventricular tachycardias (PSVT), but with no prior ECG documentation. Clinical, EPS and ablation (when performed) data were collected and andalyzed. 

Results

427 patients of 12 centers were included. Mean age was 46.3 ±16.1 and 297 (69.6%) were females. AVNRT was induced in 188 patients (typical in 181 cases, atypical in 7). Dual AV nodal physiology with or without single nodal echo beats, but with no sustained tachycardia and without evidence of accessory pathway was present in 68 patients. Ablation of the slow pathway was performed in 187/188 patients with AVNRT and in 30/68 patients with dual physiology. Among subjects with non-inducible tachycardia, ablation reduced significantly recurrences (39.5% in non-ablated vs. 16.7%; p = 0.04), with a level equivalent to those with ablated AVNRT(14.4% vs. 16.7%; p = 0.75). Procedure-related complications were similar in both groups: empirical ablation n = 1; 3.3% vs. induced tachycardia n = 6; 3.2% (p = 0.98).

Conclusions

In patients with high clinical suspicion of PSVT but non-documented and non-inducible arrhythmias, the presence of dual AV nodal physiology makes AVNRT a likely mechanism of the clinical tachycardia. Catheter ablation of slow pathway reduces the risk of recurrence to a level equivalent to those with inducible and ablated AVNRT. AVNRT (n = 188) Dual nodal physiology (n = 68) p value Age (years) 48.6 ± 16.3 41.9 ± 14.0 &lt;0.01 Female 71.8% 67.7% 0.52 Years symptomatic 9.3 ± 11.3 3.6 ± 8.1 &lt;0.01 Sudden onset 83.9% 88.0% 0.54 Abrupt end 73.4% 74.6% 0.96 Previous rate-slowing drugs 30.9% 25.0% 0.36 Previous antiarrhythmic drugs 5.9% 2.9% 0.35 Isoproterenol in EPS 70.0% 89.7% &lt;0.01

Recurrence of palpitations following electrophysiological study and ablation in suspected but undocumented paroxysmal supraventricular tachycardias: follow-up results of the BELIEVE-SVT registry

Funding Acknowledgements

Type of funding sources: None.

Introduction

ECG documentation of paroxysmal supraventricular tachycardias (PSVT) may be challenging due to their short duration and usually abrupt end.  As ablation represents first-line treatment of this pathologies, it is not uncommon that physicians refer patients to electrophysiological study (EPS) when symptoms are suggestive of PSVT even though no ECG documentation has been obtained. Our objective was to evaluate the results of ablation performed in patients with induced arrhythmias in EPS but no previous ECG documentation.

Methods

Retrospective and observational multicenter registry of consecutive patients undergoing EPS, followed or not by ablation, referred because of undocumented clinical suspicion of PSVT. We collected clinical, EPS and clinical follow-up data, along with data regarding ablation, when performed. Descriptive statistical analysis was carried out using Stata.

Results

427 patients of 12 centers were included. Mean age was 46.3 ± 16.1 and 297 (69.6%) were females. Sustained arrhythmias were induced in most patients (n = 255; 59.7%) and ablation was performed in 274 (64.2%). 10 complications (2.3% of procedures) were reported: 3 transient AV block, 2 PR interval prolongation, 2 puncture-related hematoma, 2 painful sites of puncture and 1 catheter entrapment in mitral chordae.

During a mean follow-up of 3.1 ± 2.0 years, 111 patients experienced recurrence of palpitations, mostly (n = 77; 69.4%) without ECG documentation. Clinical recurrence was more frequent in subjects who had not been ablated (41.8% vs 17.2% in ablated patients; risk ratio 2.44 (CI 95% 1.77-3.36); p &lt; 0.001). Table 1 shows types of clinical recurrences.

Conclusions

EPS in patients with high clinical suspicion of PSVT, followed by ablation when tachycardia is induced is effective in preventing future recurrences of palpitations. Early referral for EPS can, therefore, reduce visits to the emergency room, admissions and healthcare burden due to other low-yield, unnecessary tests. Type of recurrence ECG documentation 34(8.0%) ·Sinus rhythm 12(2.8%) ·Atrial tachycardia 6(1.4%) ·Typical atrioventricular nodal reentrant tachycardia 5(1.2%) ·Atrial fibrillation 5(1.2%) ·Premature ventricular beats 3(0.7%) ·Orthodromic atriventricular tachycardia 2(0.5%) Non documented recurrence 77(18.0%)

Influence of baseline inducibility and activation mapping on ablation outcomes in patients with structural heart disease and ventricular tachycardia

INTRODUCTION

Stand-alone substrate ablation has become a standard ventricular tachycardia (VT) ablation strategy. We sought to evaluate the influence of baseline VT inducibility and activation mapping on ablation outcomes in patients with structural heart disease (SHD) undergoing VT ablation.

METHODS

Single center, observational and retrospective study including consecutive patients with SHD and documented VT undergoing ablation. Baseline VT induction was attempted before ablation in all patients and VT activation mapping performed when possible. Ablation was guided by activation mapping for mappable VTs plus substrate ablation for all patients. Ablation outcomes and complications were evaluated.

RESULTS

One hundred and sixty patients were included and were classified in three groups according to baseline VT inducibility:group 1 (non inducible, n = 18), group 2 (1 VT morphology induced, n = 53), and group 3 (>1 VT morphology induced, n = 89). VT activation mapping was possible in 35%. After a median follow-up of 38.5 months, baseline inducibility of greater than 1 VT morphology was associated with a significant incidence of VT recurrence (42% for group 3 vs. 15.1% for group 2% and 5.6% for group 1, Log-rank p < .0001) and activation mapping with a lower rate of VT recurrence (24% vs. 36.3%, Log-rank p = .035). Baseline inducibility of greater than 1 VT morphology (hazards ratio [HR]: 12.05, 95% confidence interval [CI]: 1.60-90.79, p = .016) was an independent predictor of VT recurrence while left ventricular ejection fraction less than 30% (HR: 1.93, 95% CI: 1.13-3.25, p = .014) and advanced heart failure (HR: 4.69, 95% CI: 2.75-8.01, p < .0001) were predictors of mortality or heart transplantation. Complications occurred in 11.2% (5.6% hemodynamic decompensation).

CONCLUSION

Baseline VT inducibility and activation mapping may add significant prognostic information during VT ablation procedures.