Left ventricular performance during para-His pacing in patients with high-grade atrioventricular block: an acute study.

Objective: To compare changes in left ventricular (LV) performance and mechanical synchrony between atrial-based pacing with intrinsic conduction (AAI), dual-chamber para-His Pacing (DDD-PHP) and dual-chamber right ventricular septal pacing (DDD-RVS) in patients with high-grade atrioventricular block (AVB).

Results: Patients with high-grade AVB and QRS <120 ms, who had temporary intrinsic atrioventricular (AV) conduction the day after the implantation were included in the study. All patients received a biventricular pacemaker with a para-His lead in the LV port, and a RVS lead in the right ventricular port. Left ventricular three-dimensional echocardiograms, LV outlet tract-velocity time integrals (LVOT-VTI), and LV synchrony with tissue Doppler imaging were recorded during AAI, DDD-PHP, and DDD-RVS. Eleven patients were included. The mean LVOT-VTI was significant lower during DDD-RVS (19.2 ± 5.5 cm) as compared with DDD-PHP (21.4 ± 5.5 cm), P = 0.006 and AAI (21.6 ± 6.8 cm), P = 0.016. The LVEF was higher during AAI than during DDD-PHP (P= 0.02) and DDD-RVS (P< 0.01). The maximal time to peak velocity between basal segments was significant longer with DDD-RVS (95 ± 26 ms) than with AAI (72 ± 30 ms), P = 0.028, whereas no difference was observed between AAI and DDD-PHP (81 ± 42 ms), P = 0.20.

Conclusions: Acutely, DDD-PHP preserves LV systolic performance and mechanical synchrony as compared with DDD-RVS.