Right ventricular outflow tract and dual site right ventricular pacing - the comparison with apex pacing

Abstract

Recent data suggest that RV apical pacing is harmful - especially in patients with heart failure. There is some evidence that RVOT pacing or simultaneous RVA and RVOT pacing (Dual site Right Ventricular pacing - DuRVp) may be more beneficial that RVA pacing. The aim of the study was to compare hemodynamic effects of RVA, RVOT and DuRV pacing and find predictors of hemodynamic improvement. We studied 50 pts (32 m., 18 f.); mean age 72 y. (52-89), with a history of heart failure (without indications for CRT). DDD/VVI - 41/9 pts. Cardiac performance was evaluated temporarily throughout different modes of pacing, by impedance cardiography (BioZ.com) during pacemaker implantation procedure. Measurements were collected in 3 min periods, with adaptation periods of 3 min., throughout RVA and RVOT and RVA + RVOT pacing in turn. No AV delay optimization prior to measurement, AV delay was set - 20ms less than AV of fully preexited ventricle QRS pattern. Cardiac index, lowest in RVAp mode, increased in RVOTp and more in DuRVp mode (2,34; 2,45; 2,57 [l/min/m2] respectively; ANOVA-LSD p<0,001). 64,7% pts. had higher CI in RVOTp vs RVAp (36,0% pts. more than 10% = responders), 78,4% pts. had higher CI in DuRVpvs RVAp (45,1% responders), 75,5% pts. had higher CI in DuRVp vs RVOTp (34,0% responders). Responders to RVOTp and DuRVp vs RVAp had lower LVEF and CI in RVAp and longer QRS duration than non-responders. Pts who were responders to RVOTp vs. RVAp had no additional benefit of DuRVp. RVOT pacing provides significantly higher cardiac performance in comparison to RVAp. DuRVp is even more hemodynamically effective. The improvement in systolic performance is observed mainly in pts with impaired baseline systolic function. RVOTp and DuRVp may be considered as alternatives to RVA for HF patients with ventricular pacing indications but without current CRT indications or in cases when the LV lead implantation is impossible.