Electrical parameters, programming and acute complications
The acute electrical parameters obtained at implant are represented in table 1. The mean QRS width in the entire cohort was significantly reduced from 144±32 ms at baseline to 116±16 ms during HBP or LBBAP, p=0.001 (Figure 4). The 5 patients with LVSP also significantly reduced QRS width from 141±22 ms to 114±15 ms, p=0.029 (Figure 2). The average penetration of the lead in the interventricular septum in the 5 patients with LVSP evidenced by contrast through the sheath was 7.4±0.54 mm (baseline mean interventricular septal thickness in these patients was 8.2±0.84 mm).
Patient #7 had a significant increase of LBB lead pacing threshold at day 4 post-implant evidenced by the sudden appeareance of bradycardia on remote monitoring. The initial implant procedure was challenging with multiple attempts of fixation due to poor lead stability in complex anatomy (D-TGA with Senning correction)(Figure 3). This patient underwent repositioning of the lead in the same location with excellent electrical parameters. A second back-up pacing lead was implanted in the subpulmonic ventricle and connected to a CRT-P generator. No other acute complications occurred in the study population.