Repositioning and extraction of stylet-driven pacing leads with extendable helix used for left bundle branch area pacing

Conventional stylet-driven leads with extendable helix can be implanted successfully for left bundle branch area pacing (LBBAP) with a low acute complication rate. We report two cases in which lead repositioning after a first unsuccessful attempt to LBBAP was associated with fracture of the helix rotating mechanism and failure to fully extract the pacing lead.     

New‐onset intrinsic and paced QRS morphology of right bundle branch block pattern after atrioventricular nodal ablation: Longitudinal dissociation or anatomical bifurcation?

We performed left bundle pacing combined with atrioventricular nodal (AVN) ablation in a patient with persistent atrial fibrillation and refractory symptomatic heart failure. The major findings were new‐onset intrinsic and paced QRS morphology of right bundle branch block (RBBB) pattern after AVN ablation which was performed at a more atrial site compared with the pacing site and the paced RBBB pattern could not be corrected regardless of the pacing output. Longitudinal dissociation cannot explain this observation, while anatomical separation could. We also confirm this was proximal left bundle pacing rather than His bundle pacing.     

Permanent HIS bundle Pacing Feasibility in Routine Clinical Practice: Experience from an Indian Center

There is a paucity of experience regarding His bundle pacing (HBP) at laboratories initially attempting the procedure, especially in the Indian scenario. Patient who underwent HBP were selected for pacing therapy or in lieu of cardiac resynchronization therapy (CRT) at a single center. Among 22 patients attempted, 19 patients underwent successful implant, achieving selective HBP in 14 patients. There was a significant improvement in left ventricular ejection fraction (LVEF) (49.3 ± 9.3 vs. 36.7 ± 9.2) in the LV dysfunction subgroup (n = 6). Over a follow-up of 15 ± 6.5 months, thresholds were stable in all except one patient, and there was no requirement of lead revision. In summary, we found that HBP is a feasible option for achieving physiological pacing.     

New criterion to determine left bundle branch capture on the basis of individualized His bundle or right ventricular septal pacing

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左束支区域起搏的现状和展望

希氏束和左束支区域的生理性起搏较右室心尖部起搏明显改善心脏的电机械同步性,改善心功能。希氏束起搏是最生理的起搏方式,而且可纠正大部分的完全性左束支传导阻滞,改善心脏再同步化,但也存在起搏阈值高、R波振幅低和潜在的希氏束远端病变风险。左束支呈扇形分布左室间隔内膜面下,起搏阈值和R波振幅同右室心尖部相似,而且左束支近端起搏可纠正病变于希氏束的左束支传导阻滞,可作为心脏再同步化治疗的备选方案。现就左束支的解剖、左束支区域起搏的电生理特点和左束支区域起搏的临床应用进行综述。     

Improved outcomes of conduction system pacing in heart failure with reduced ejection fraction: A systematic review and meta-analysis

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Right bundle branch pacing: Criteria,characteristics, and outcomes

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Cardiac troponin release following left bundle branch pacing

Left bundle branch pacing (LBBP) has emerged as an alternative to His bundle pacing (HBP) to achieve physiologic ventricular stimulation. The extent of myocardial injury during permanent LBBP implantation is currently not known. The aim of the study was to prospectively assess the extent of myocardial injury during LBBP implantation. Cardiac troponin (cTn) levels were measured at baseline and 6–12 h following permanent LBBP. The number of attempts to achieve LBBP was documented. Troponin levels were measured in a control population undergoing other electrophysiology procedures including HBP, other devices involving right ventricular (RV) pacing, radiofrequency ablation for atrial fibrillation (AF) and supraventricular tachycardia (SVT). Significant elevation of troponin (SET) was defined as threefold increase above the upper reference limit (URL) for cTn. Between December 2019 and April 2020, 204 were prospectively enrolled: LBBP in 98 and Control group 106 (SVT, 55; AF, 20; HBP, 17; other devices, 14). SET (>3× URL) was seen in 49.4% of patients in the LBBP group compared to 58.4% in the control group (p = .23). Peak troponin levels were greater in the control group compared to the LBBP group (230.3 ± 320.1 vs. 87.4 ± 71.3 pg/ml; p = .0001). Compared to LBBP (49.4%), SET was observed less frequently following HBP (17.5%; p = .01), and other device implantation (29%; p = .15). Patients requiring >2 attempts (n = 33) had significantly higher incidence of SET compared to <2 attempts (n = 56; 66.7% vs. 39.3%; p = .01). LBBP implantation is associated with myocardial injury. Asymptomatic troponin release following LBBP is less than or comparable to other interventional electrophysiology procedures.     

希氏束起搏进展

希氏束起搏是一种生理性的起搏模式。较传统右心室起搏相比,能够改善电-机械活动的同步性及血流动力学,有较好的临床获益。本文就希氏束起搏的研究进展做一综述。     

Effect of scar and His–Purkinje and myocardium conduction on response to conduction system pacing

Introduction

Conduction system pacing (CSP), in the form of His bundle pacing (HBP) or left bundle branch pacing (LBBP), is emerging as a valuable cardiac resynchronization therapy (CRT) delivery method. However, patient selection and therapy personalization for CSP delivery remain poorly characterized. We aim to compare pacing-induced electrical synchrony during CRT, HBP, LBBP, HBP with left ventricular (LV) epicardial lead (His-optimized CRT [HOT-CRT]), and LBBP with LV epicardial lead (LBBP-optimized CRT [LOT-CRT]) in patients with different conduction disease presentations using computational modeling.

Methods

We simulated ventricular activation on 24 four-chamber heart geometries, including His–Purkinje systems with proximal left bundle branch block (LBBB). We simulated septal scar, LV lateral wall scar, and mild and severe myocardium and LV His–Purkinje system conduction disease by decreasing the conduction velocity (CV) down to 70% and 35% of the healthy CV. Electrical synchrony was measured by the shortest interval to activate 90% of the ventricles (90% of biventricular activation time [BIVAT-90]).

Results

Severe LV His–Purkinje conduction disease favored CRT (BIVAT-90: HBP 101.5 ± 7.8 ms vs. CRT 93.0 ± 8.9 ms, p < .05), with additional electrical synchrony induced by HOT-CRT (87.6 ± 6.7 ms, p < .05) and LOT-CRT (73.9 ± 7.6 ms, p < .05). Patients with slow myocardium CV benefit more from CSP compared to CRT (BIVAT-90: CRT 134.5 ± 24.1 ms; HBP 97.1 ± 9.9 ms, p < .01; LBBP: 101.5 ± 10.7 ms, p < .01). Septal but not lateral wall scar made CSP ineffective, while CRT was able to resynchronize the ventricles in the presence of septal scar (BIVAT-90: baseline 119.1 ± 10.8 ms vs. CRT 85.1 ± 14.9 ms, p < .01).

Conclusion

Severe LV His–Purkinje conduction disease attenuates the benefits of CSP, with additional improvements achieved with HOT-CRT and LOT-CRT. Septal but not lateral wall scars make CSP ineffective.