B-PO01-101 COMPARISON OF RIGHT VENTRICULAR, DEEP SEPTAL, AND BIVENTRICULAR PACING

Abstract

Left septal pacing results in comparable electrical activation and hemodynamics to LBB, His bundle, or biventricular (BIV) pacing. This study compared acute electrogram and echocardiographic parameters between right ventricular (RV), deep septal, and BIV pacing. Deep septal pacing was performed by advancing an active fixation lead across the septum guided by QRS duration and morphology. RV, deep septal, and BIV pacing were compared with respect to QRS, left ventricular activation time as measured from stimulus to the latest peak of V5 or V6 (LVAT), LV ejection fraction (LVEF), and global longitudinal strain (GLS). In a subset of patients with adequate quality electrograms, paced vectorcardiographic ECG area was also compared. The study cohort had 35 patients (34% female, 79±9 years, 64% nonischemic cardiomyopathy, baseline QRS 167 ± 28ms, LVEF 30 ± 9%, LV end diastolic dimension 5.4 ± 0.9 cm). The deep septal pacing threshold was 0.6±0.2 mV and 0.6 ms. Paced QRS duration was 179± 23 ms with RV pacing, 135 ± 21 ms with deep septal pacing and 144 ±15 ms with BIV pacing (p<0.01, 0.2 for deep septal vs. BIV). LVAT was 101±20 ms with RV pacing, 78 ± 15 ms with deep septal pacing, and 80 ± 18 ms with BIV pacing (p<0.01, p=0.9 for deep septal vs. BIV). LVEF and GLS were 29 ± 9% and 9±4% with RV pacing, 36 ± 10% and 10 ± 4% with deep septal pacing, and 35 ± 10% and 10 ± 3% with biventricular pacing respectively (p=0.01) In a subset of patients (n=22) QRS area was 62 ± 27 ms*mV with deep septal pacing and 69 ± 32 ms*mV with BIV (p=0.3). In patients with QRS prolongation, deep septal and BIV pacing result in similar acute electrical and echocardiographic left ventricular activation.