High RVOT septal pacing achieved a narrower QRS duration (117.86 ms vs 140.29 ms, p<0.001) and better 6-minute walk test results (473 m vs 308 m, p<0.001) than RV apical pacing.
Observational (n=69)
Does RVOT pacing improve left ventricular electromechanical activation and functional capacity compared to RV apical pacing in patients with pacemaker-dependent complete heart block?
High RVOT septal pacing provides better electromechanical synchrony and functional capacity than traditional RV apical pacing in patients with complete heart block.
Absolute Event Rate: 117.86% vs 140.29%
p-value: p=< 0.001
Right ventricular (RV) apical pacing, induces asynchronous ventricular contraction and impairs cardiac function. Alternative sites of pacing particularly right ventricular outflow tract (RVOT) may have a more favorable hemodynamic profile, physiological left ventricular (LV) activation and normal ventricular contraction pattern. The Aim of the study was to find out the best alternative sites to RV apex for permanent pacemaker (PM) lead fixation in the RVOT, based on the width of the QRS in the surface ECG. The study included 69 patients with pacemaker-dependent complete heart block; 35 with active pacemaker lead fixation in the site which achieved narrowest max. QRS duration in the RVOT (group 1) and 34 with active pacemaker lead fixation in RV apex (group 2). High RVOT septum was the site which achieved the narrowest QRS duration on surface ECG (117.86 ± 8.43 ms) when compared with RV apex (140.29 ± 13.14) ( p < 0.001). There was a marked LV asynchrony after 3 months in group 2; IVMD (51.67 ± 14.06 ms), LVPEP (191.55 ± 36.56 ms), RVPEP (142.45 ± 23.11 ms) and SPWMD (125.64 ± 34.15 ms) when compared to group 1; IVMD (26.93 ± 12.44 ms), LVPEP (107.32 ± 45.28 ms), RVPEP (76.11 ± 27.66 ms) and SPWMD (78.15 ± 36.45 ms) ( p < 0.001). Tissue Doppler Imaging revealed marked difference on the opposing LV segments mainly between mid-septal and mid-lateral in group 2. The 6 MWT was much better in group 1 patients (473 ± 240 m) than in group 2 patients (308 ± 221 m) ( p < 0.001). High RVOT septum is the ideal site for PM lead implantation. Compared with RV apical pacing, it is associated with improvement in functional and hemodynamic parameters over medium-term follow-up.
Roshdy et al. (2016) conducted an observational in pacemaker-dependent complete heart block (n=69). Active pacemaker lead fixation in the RVOT site achieving narrowest max QRS duration (High RVOT septum) vs. Active pacemaker lead fixation in RV apex was evaluated on QRS duration on surface ECG (p=< 0.001). High RVOT septal pacing achieved a narrower QRS duration (117.86 ms vs 140.29 ms, p<0.001) and better 6-minute walk test results (473 m vs 308 m, p<0.001) than RV apical pacing.