Cardiac pacing is the only effective therapy for patients with symptomatic bradyarrhythmia. Traditional right ventricular apical pacing causes electrical and mechanical dyssynchrony resulting in left ventricular dysfunction, recurrent heart failure, and atrial arrhythmias. Physiological pacing activates the normal cardiac conduction, thereby providing synchronized contraction of ventricles. Though His bundle pacing (HBP) acts as an ideal physiological pacing modality, it is technically challenging and associated with troubleshooting issues during follow-up. Left bundle branch pacing (LBBP) has been suggested as an effective alternative to overcome the limitations of HBP as it provides low and stable pacing threshold, lead stability, and correction of distal conduction system disease. This paper will focus on the implantation technique, troubleshooting, clinical implications, and a review of published literature of LBBP.

Left bundle branch pacing: A comprehensive review.

Electrophysiological characteristics of septal perforation during left bundle branch pacing.

PVC-guided lead placement would help in final positioning of the lead and avoid septal perforation into the left ventricular cavity. Introduction Physiological pacing has witnessed a rapid growth in the last decade. His bundle pacing (HBP) provides electrical and mechanical synchrony but may be limited by high pacing thresholds and higher need for lead revisions. Left bundle branch pacing (LBBP) has recently been shown to be a promising alternative to HBP. Several criteria for successful left bundle capture have been proposed but need to be validated. LBBP involves advancing the lead deep into the septum by rapid rotations. The goal is to place the lead adjacent to the left bundle branch in the left ventricular (LV) subendocardial region without perforation into the LV cavity. We describe premature ventricular complex (PVC)-guided lead implantation as a novel approach to perform LBBP.

Left bundle branch pacing guided by premature ventricular complexes during implant

His bundle pacing (HBP) has evolved as the most physiological form of pacing but associated with limitations. Recently, left bundle branch pacing (LBBP) is emerging as an effective alternative strategy for HBP. Our study was designed to assess the feasibility, efficacy, electrophysiological parameters, and mid-term outcomes of LBBP in Indian population. All patients requiring permanent pacemaker implantation for symptomatic bradycardia and heart failure were prospectively enrolled. Echocardiography, QRS duration, pacing parameters, left bundle (LB) potentials, paced QRS duration, and peak left ventricular activation time (pLVAT) were recorded. LBBP was successful in 93 out of 99 patients (94% acute success). Mean age was 62.6 ± 13 years, male 59%, diabetes 69%, and coronary artery disease 65%. Follow-up duration was 4.8 months (range1–12 months). Indication for pacing included atrioventricular (AV) block 43%, cardiac resynchronization therapy 44%, and AV node ablation 4%. LB potential was noted in 37 patients (40%). QRS duration reduced from 144.38 ± 34.6 at baseline to 110.8 ± 12.4 ms after LBBP (p < 0.0001). Pacing threshold was 0.59 ± 0.22 V and sensed R wave 14.14 ± 7.19 mV, and it remained stable during follow-up. Lead depth in the septum was 9.62 mm. LV ejection fraction increased from 44.96 to 53.3% after LBBP (p < 0.0001). One died due to respiratory tract infection on follow up. LBBP is a safe and effective strategy (94% acute success) of physiological pacing. The pacing parameters remained stable over a period of 12 months follow-up. LBBP can effectively overcome the limitations of HBP.

Mid-term feasibility, safety and outcomes of left bundle branch pacing–single center experience

A 61-years-old male underwent left bundle branch pacing for nonischemic dilated cardiomyopathy with recurrent heart failure. Left bundle branch pacing (LBBP) resulted in reduction in QRS duration along with improvement in left ventricular ejection fraction (LVEF) to 64% during follow-up. Two years after implantation he had recurrence of symptoms along with decline in LVEF to 51%. Late lead dislodgement was diagnosed and re-do LBBP was planned. The lead was extracted en-masse without complication and a new 3830 lead was positioned deep inside the proximal septum to capture the left bundle. Postprocedure echocardiography showed no ventricular septal defect or damage to tricuspid leaflet.

Late dislodgement of left bundle branch pacing lead and successful extraction.

Electroanatomical Mapping-Guided Low Fluoroscopy Left Bundle Branch Pacing.

Left bundle branch pacing (LBBP) is emerging as an alternative to His bundle pacing that overcomes the latter's limitations. Several studies have reported on the safety, efficacy, and electrophysiological properties of LBBP, while postoperative success rates range from 80.5% to 94%. The left posterior fascicle is composed of broad bands of fibers coursing inferiorly and posteriorly toward the papillary muscle, while the anterior fascicle is a thin, tendon-like structure. We report a case of a 70-year-old man in whom left posterior fascicular pacing was done after LBBP failed. We were able to demonstrate all the features of left posterior fascicular capture, including fascicular potential and a left anterior hemiblock pattern, using surface 12-lead electrocardiography. Left posterior fascicular pacing could be an alternative technique when attempts to deploy LBBP fail.

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Left Posterior Fascicular Pacing.

Objectives Left bundle branch pacing (LBBP) provides physiological pacing at low and stable threshold. The safety and efficacy of LBBP in elderly population is unknown. Our study was designed to assess the safety, efficacy and electrophysiological parameters of LBBP in octogenarian (≥80 years) population. Results LBBP was successful in 10 out of 11 patients. Mean age 82.1 ± 2.5 yrs. Follow up duration 7.7 months(range4–10). Indication for pacing included atrioventricular (AV) block 5 patients, Left bundle branch block (LBBB) with low ejection fraction (EF) 4 patients, sinus node dysfunction in 1. QRS duration reduced from 145.9 ± 27.7ms to 107.1 ± 9.5ms (p value0.00001) LV ejection fraction increased from 47.6% to 58.4% after LBBP (p value0.017). Pacing threshold was 0.58 ± 0.22 V and sensed R wave 17.35 ± 6.5 mV and it remained stable during follow up. LBBB with low EF patients also showed similar reduction in QRS duration along with improvement in LVEF. Conclusion LBBP is a safe and effective strategy (91% acute success) of physiological pacing in elderly patients. LBBP also provided effective resynchronization therapy in our small group of elderly patients. The pacing parameters remained stable over a period of 10 months follow up.

Surya Kumar

Papers

Mid-term feasibility, safety and outcomes of left bundle branch pacing–single center experience

Electroanatomical Mapping-Guided Low Fluoroscopy Left Bundle Branch Pacing.

Left Posterior Fascicular Pacing.

Feasibility, safety and outcomes of left bundle branch pacing in octogenarians.