Left bundle branch pacing for symptomatic bradycardia: Implant success rate, safety, and pacing characteristics

Abstract

BACKGROUND In patients with or without left bundle branch block, left bundle branch pacing (LBBP) can produce near normalization of QRS duration (QRSd). This has recently emerged as an alternative technique to His bundle pacing.OBJECTIVES The purpose of this study was to characterize a novel approach for LBBP in patients with bradycardia indications for pacing and to assess implant success rate and midterm safety.METHODS Patients with bradycardia indications for pacing underwent LBBP by a trans-ventricular-septal method in the basal ventricular septum. Procedural success, pacing parameters, and complications were assessed at implantation and at 3 months follow-up.RESULTS This prospective study evaluated 87 patients (sinus node dysfunction 67.8%; atrioventricular conduction disease 32.2%) undergoing pacemaker implantation. LBBP implantation succeeded in 80.5% (70/87) of patients and the remaining 17 patients received right ventricular septal pacing. The procedure time of LBBP implantation was 18.0 6 8.8 minutes with a fluoroscopic exposure time of 3.9 6 2.7 minutes. LBBP produced narrower electrocardiographic QRSd than did right ventricular septal pacing (113.2 6 9.9 ms vs 144.4 6 12.8 ms; P , .001). There were no major implantationrelated complications. The pacing threshold was low (0.76 6 0.22 V at implantation and 0.71 6 0.23 V at 3 months), with no loss of capture or lead dislodgment observed.CONCLUSION This study demonstrates that in patients with standard bradycardia pacing indications, LBBP results in QRSd , 120 ms in most patients and can be performed successfully and safely in the majority of patients.

How to implant left bundle branch pacing lead in routine clinical practice

“…LBBP is defined as follows: (a) a paced QRS morphology on 12‐lead electrocardiogram (ECG) shows the pattern of right bundle branch conduction delay (RBBD) or improving the LBB conduction in patients with LBBB; (b) a left bundle branch potential can be recorded; and (c) a fast peak left ventricular activation time (LVAT) in V5/V6 on the surface 12‐lead ECG is present. The paced (QRSd) is usually less than 120 ms according to our study in patients with bradycardia (N = 70) …”

“…Our previous study demonstrated the procedural and clinical feasibility of LBBP via a transventricular‐septal approach . Subsequently, we reported the success rate, safety, and 3‐month follow‐up outcomes of LBBP . With further investigations showing a similar effect of LBBP when compared with HBP, more electrophysiologists have begun to practice this technique.…”

“…Thus, the left bundle branch pacing (LBBP) has emerged as an alternative method for physiological pacing . LBBP is characterized with a low and stable pacing capture threshold, relatively narrow QRS duration (QRSd) due to fast left ventricular activation, and direct excitation of the diseased left bundle branch (LBB) . Our previous study demonstrated the procedural and clinical feasibility of LBBP via a transventricular‐septal approach .…”

“… LBBP is defined as follows: (a) a paced QRS morphology on 12‐lead electrocardiogram (ECG) shows the pattern of right bundle branch conduction delay (RBBD) or improving the LBB conduction in patients with LBBB; (b) a left bundle branch potential can be recorded; and (c) a fast peak left ventricular activation time (LVAT) in V5/V6 on the surface 12‐lead ECG is present. The paced (QRSd) is usually less than 120 ms according to our study in patients with bradycardia (N = 70) Selective LBBP (S‐LBBP) is defined by the following criteria: (a) the paced QRS morphology shows RBBD, usually with an rSR pattern in V1 due to delayed activation of the right bundle branch (RBB); (b) there is an isoelectric interval between the pacing spike and ECG QRS onset; (c) the interval between the pacing spike to QRS onset is almost identical to the interval from the left bundle potential to QRS onset; and (d) a local ventricular electrogram (EGM) is present as a discrete component (Figure A). Nonselective LBBP (NS‐LBBP) is defined by the following criteria: (a) the paced QRS morphology shows the RBBD, usually with a QR pattern in V1 due to delayed RV activation; (b) there is no isoelectric interval between the pacing spike and surface ECG QRS onset; and (c) the local ventricular EGM shows direct capture of local tissue by the pacing stimulus (Figure B).…”

“…Then, pacing with an output of 2.0 V/0.5 ms or 5 V/0.5 ms is applied. The paced QRS morphology shows the LBBB morphology, usually characterized with an ECG QRSd less than 150 ms, a notch (also called “W” waveform) at the nadir of the QRS waveform in ECG‐lead V1, a positive QRS in lead II, and biphasic QRS in lead III. The initial lead fixation at this location is conducted with four to five clockwise turns of the pacing lead.…”