Electroanatomical mapping-guided left bundle branch area pacing in patients with structural heart disease and advanced conduction abnormalities

Abstract

Aims: Left bundle branch area pacing (LBBAP) can be technically challenging and fluoroscopy-intense. Three-dimensional electroanatomical mapping (EAM) facilitates non-fluoroscopic lead navigation and electrogram mapping. We sought to prospectively evaluate the feasibility, safety, and outcomes of routine EAM-guided LBBAP in patients with structural heart disease (SHD) and advanced conduction abnormalities.

Methods and results: Consecutive patients with SHD and conduction abnormalities who underwent an attempt at EAM-guided LBBAP were included. The feasibility, safety, procedural, and mid-term outcomes were evaluated. Electrical, echocardiographic, and clinical parameters were assessed at implantation and last follow-up. Thirty-two patients (68 ± 18 years; 19% female) were included, of which 75% had intrinsic QRS > 150 ms, 53% left bundle branch block, and 25% right bundle branch block. Primary EAM-guided LBBAP was successful in 29 patients (91%). The procedural duration was 95 (70-110) min, total fluoroscopy time 0.93 (0.40-1.73) min, and total fluoroscopy dose 35.4 (20.5-77.2) cGy cm2. Paced QRS duration (QRSd) was significantly shorter than intrinsic QRSd (121.9 ± 10.7 vs. 159.2 ± 34.4 ms; P < 0.001) and remained stable during the mean follow-up of 7.0 ± 5.9 months. The LBBAP capture threshold was 0.57 ± 0.23 V/0.4 ms at implantation and remained low during follow-up (0.58 ± 0.18 V/0.5 ± 0.2 ms; P = 0.877). Overall left ventricular ejection fraction improved significantly from 44.2 ± 14.3% at baseline to 49.4 ± 13.1% at follow-up (P = 0.009), New York Heart Association class from 2.4 ± 0.6 to 1.8 ± 0.6 (P = 0.002), respectively. No complications occurred that required intervention.

Conclusion: Routine near-zero fluoroscopy EAM-guided LBBAP can safely be performed in patients with SHD and advanced conduction abnormalities with high success rates and favourable mid-term outcomes. Further studies are needed to investigate whether the use of EAM improves the overall outcome of conduction system pacing and to identify specific patient populations who benefit the most from EAM-guided lead implantation.

Keywords: Cardiac implantable electronic device; Electroanatomical mapping; Implantation technique; Left bundle branch area pacing; Radiation exposure.

Figure 1

Targeted LBBP guided by the EnSite Precision system in a patient with non-ischaemic CMP and advanced infranodal conduction disease (A). Electroanatomical maps with tagged locations at distal HB (yellow dots), IVS (blue dots), and LBB (red dot) in right anterior oblique (upper panel) and left anterior oblique cranial (lower panel) projections; the green icon represents the visualized roving lead tip (green arrow) at the target LBB position (B). Twelve-lead ECGs and unipolar electrograms from the lead tip at the mapped HB (A) and target LBB position at baseline (C) and during NS- and S-LBBP (D). Note the LB injury current (C) and discrete component on the unipolar electrogram during S-LBBP (D, arrow). CMP, cardiomyopathy; ECG, electrocardiogram; HB, His bundle; IVS, interventricular septum; LBBP, left bundle branch (LBB) pacing; NS, non-selective; S, selective.

Figure 2

Targeted LBBP guided by the EnSite Precision system in a patient with ischaemic CMP and LBBB. (A) Electroanatomical maps with tagged locations at the HB region (yellow dots), IVS (blue dots), and LPF (red dot) in right anterior oblique (left panel) and LAO cranial (right panel) projections; the green icon represents the visualized roving lead tip at the target position. Note the more distal LPFP. (B) Contrast fluoroscopic image in LAO projection demonstrating the position of the LBBP lead in the IVS (arrow). (C) Echocardiographic image in apical four-chamber view confirming the location of the LBBP lead tip deep in the LV septum (arrow). (D) Twelve-lead ECGs at 12-month follow-up demonstrating intrinsic conduction, NS-LPFP only, and NS-LPFP with intrinsic RBB conduction after AVD opt. AVD opt, atrioventricular delay optimization; CMP, cardiomyopathy; ECG, electrocardiogram; HB, His bundle; IVS, interventricular septum; LAO, left anterior oblique; LBBP, left bundle branch pacing; LPFP, left posterior fascicle (LPF) pacing; NS, non-selective; RA, right atrial, RV, right ventricular.

Figure 3

Targeted LBBP guided by the EnSite Precision system in a patient with severe dilated CMP and advanced infranodal conduction disease. (A) Twelve-lead ECG and unipolar electrogram from the lead tip at the proximal HB showing LBBB with wide QRS (238 ms) and prolonged HV interval (106 ms). (B) Electroanatomical maps with tagged locations at the HB region (yellow dots), right ventricular septum (turquoise dot), IVS (blue dots), and LBB (red dot) in right anterior oblique (upper panel) and left anterior oblique cranial (lower panel) projections; the green icon represents the visualized roving lead tip at the target LBB position. (C) Baseline CMR image in apical four-chamber view demonstrating severe dilatation of the left ventricle. (D) Post-operative chest radiograph in posterior–anterior view. (E) Twelve-lead ECGs at 6-month follow-up demonstrating LBBB and 2:1 conduction in the right bundle during atrial pacing (600 ms), intrinsic conduction with left anterior fascicular block during sinus rhythm (1050 ms); LVSP and NS-LBBP during threshold testing (600 ms). See text for more information. CMP, cardiomyopathy; CMR, cardiovascular magnetic resonance; ECG, electrocardiogram; HB, His bundle; HV, His-ventricular; IVS, interventricular septum; LBBB, left bundle branch block; LBBP, left bundle branch (LBB) pacing; LVSP, left ventricular septal pacing; NS, non-selective.

Figure 4

Procedural outcomes of EAM-guided LBBAP. Median total fluoroscopy time (FT) and fluoroscopy dose (FD) (A) and changes in QRSd with LBBAP (B) in the overall population. EAM, electroanatomical mapping; LBBAP, left bundle branch area pacing.

Figure 5

Echocardiographic (A) and clinical (B) responses of the entire cohort after left bundle branch area pacing. LVEF, left ventricular ejection fraction; NYHA, New York Heart Association.