Left bundle branch pacing lead for sensing ventricular arrhythmias in implantable cardioverter-defibrillator: A pilot study (LBBP-ICD study).

BACKGROUND: Left bundle branch pacing (LBBP) has been suggested as an alternative modality for biventricular pacing in cardiac resynchronization therapy (CRT)-eligible patients. As it provides stable R-wave sensing, LBBP has been recently used to provide sensing of ventricular arrhythmia in patients receiving implantable cardioverter-defibrillator (ICD) with CRT. OBJECTIVE: The aim of this study was to analyze the long-term safety and efficacy of the LBBP lead for appropriate detection of ventricular arrhythmia and delivery of antitachycardia pacing (ATP) in patients requiring defibrillator therapy with CRT. METHODS: CRT-eligible patients who underwent successful LBBP-optimized ICD and LBBP-optimized CRT with defibrillator were enrolled. The LBBP lead was connected to the right ventricular-P/S port after capping the IS-1 connector plug of the DF-1-ICD lead. LBBP-optimized ICD or LBBP-optimized CRT with defibrillator was decided on the basis of correction of conduction system disease. Documented arrhythmic episodes and therapy delivered were analyzed. RESULTS: Thirty patients were enrolled. The mean age was 59.7 ± 10.5 years. LBBP resulted in an increase in left ventricular ejection fraction from 29.9% ± 4.6% to 43.9% ± 11.2% (P < .0001). During a mean follow-up of 22.9 ± 12.5 months, 254 ventricular arrhythmic events were documented. Appropriate events (n = 225 [89%]) included nonsustained ventricular tachycardia (VT) (n = 212 episodes [94%]), VT (n = 8 [3.5%]), and ventricular fibrillation (n = 5 [2.5%]). ATP efficacy in terminating VT was 75%. Eleven percent of episodes (n = 29) were inappropriately detected because of T-wave oversensing. Inappropriate therapy (ATP) was delivered for 14 episodes (5.5%). Three patients (10%) had worsening of tricuspid regurgitation. CONCLUSION: Sensing from the LBBP lead for arrhythmia detection is safe as ∼90% of the episodes were detected appropriately. Future studies with a dedicated LBBP-defibrillator lead along with algorithms to avoid oversensing can help in combining defibrillation with conduction system pacing.

Observations of interventricular septal behavior during left bundle branch pacing.

INTRODUCTION: Left bundle branch pacing (LBBP) involves the deployment of the lead deep inside the septum. Penetration of the septum by the lead depends on the texture of the septum, rapidity of rotations, operator experience, and implantation tools. OBJECTIVES: The aim of our study was to assess the behavior of the lumenless lead during rapid rotations and the physiological property of the interventricular septum(IVS) during LBBP. METHODS: Patients undergoing LBBP between January 2021 and December 2022 were retrospectively included in the study. RESULTS: Among 255 attempted patients, 20 (7.9%) had procedural failure(no LBB capture-four, inability to penetrate septum-seven, and dislodgements after sheath removal-nine). Septal penetration achieved in 248/255 patients (97.2%). Lead movement inside the IVS was assessed by lead traverse time. Based on the behavior of the IVS (n = 255), three different responses were noted. Type-I response(normal/firm septum) in 93.7% (n = 239) characterized by constant and progressive movement of lead. Neither perforation nor further change in premature-ventricular-complex morphology beyond M-beat were observed despite additional few unintentional rotations indicating the protective mechanism of LV-endocardium. Type-II response(soft/cheesy septum) in 3.5% (n = 9) characterized by hyper-movement of lead without resistance due to altered texture of septum and poor LV subendocardial barrier resulting in perforation. No patients in this group had LV dysfunction or associated coronary artery disease. In type-III response, seen in 2.8% (n = 7), lead could not be penetrated due to scar in IVS. CONCLUSION: Three different patterns of responses were observed during LBBP. The most distinct type-ll response was associated with soft/cheesy septum with hyper-movement of the lead predisposing for future dislodgments in patients without structural heart disease.

MAgnetic resonance imaging based DUal lead cardiac Resynchronization therapy: A prospectIve Left Bundle Branch Pacing study (MADURAI LBBP study).

BACKGROUND: Cardiac resynchronization therapy (CRT) is a class I indication for left ventricular ejection fraction (LVEF) ≤35% and heart failure (HF). Left bundle branch block (LBBB)-associated nonischemic cardiomyopathy (LB-NICM) with minimal or no scar by cardiac magnetic resonance (CMR) imaging may be associated with excellent prognosis following CRT. Left bundle branch pacing (LBBP) can achieve excellent resynchronization in LBBB patients. OBJECTIVES: The purpose of this study was to prospectively assess the feasibility and efficacy of LBBP with or without a defibrillator in patients with LB-NICM and LVEF ≤35%, risk stratified by CMR. METHODS: Patients with LB-NICM, LVEF ≤35%, and HF were prospectively enrolled from 2019 to 2022. If the scar burden was <10% by CMR then LBBP only (group I) and if ≥10% then LBBP + implantable cardioverter-defibrillator (ICD) (group II) was performed. Primary endpoints were (1) echocardiographic response (ER) [ΔLVEF ≥15%] at 6 months; and (2) composite of time to death, heart failure hospitalization (HFH), or sustained ventricular tachycardia (VT)/ventricular fibrillation (VF). Secondary endpoints were (1) echocardiographic hyperresponse (EHR) [LVEF ≥50% or ΔLVEF ≥20%] at 6 and 12 months; and (2) indication for ICD upgrade [persistent LVEF <35% at 12 months or sustained VT/VF]. RESULTS: One hundred twenty patients were enrolled. CMR showed <10% scar burden in 109 patients (90.8%). Four patients opted for LBBP+ICD and withdrew. LBBP-optimized dual-chamber pacemaker (LOT-DDD-P) was performed in 101 patients and LOT-CRT-P in 4 patients (group I; n = 105). Eleven patients with scar burden ≥10% underwent LBBP+ICD (group II). During mean-follow-up of 21 ± 12 months, the primary endpoint of ER was observed in 80% (68/85 patients) in group I vs 27% (3/11 patients) in group II (P = .0001). Primary composite endpoint of death, HFH, or VT/VF occurred in 3.8% in group I vs 33.3% in group II (P <.0001). Secondary endpoint of EHR (LVEF≥50%) was observed in 39.5% vs 0%, 61.2% vs 9.1%, and 80% vs 33.3% at 3, 6, and 12 months in groups I and II, respectively. CONCLUSION: CMR-guided CRT using LOT-DDD-P seems to be a safe and feasible approach in LB-NICM and has the potential to reduce health care costs.

Left bundle branch pacing-optimized implantable cardioverter-defibrillator (LOT-ICD) for cardiac resynchronization therapy: A pilot study.

Left bundle branch pacing (LBBP) involves direct capture of left bundle fibers by placing the lead deep inside the interventricular septum. Several studies have shown the feasibility and efficacy of LBBP as an alternative modality for cardiac resynchronization therapy (CRT). This paper describes approach for providing cost effective CRT with defibrillator (CRT-D) by LBBP and dual chamber implantable cardioverter defibrillator (ICD) which we label as LBBP optimized ICD (LOT-ICD). LBBP was performed using C315 sheath and 3830 Selectsecure lead in all patients by premature ventricular complex guided approach. In patients with complete correction of conduction system disease, IS-1 connector plug of the IS-1/DF-1 lead was capped and 3830 lead connected to the dual chamber ICD pulse-generator at RV-P/S port. LOT-ICD provided stable R-wave sensing for arrhythmia monitoring and resulted in cost-effective resynchronization therapy at reduced fluoroscopy duration and radiation dose.