Right Ventricular Apical Pacing And Right Ventricular Inflow Tract Pacing On Myocardial Perfusion And Function Of Comparative Study

Objective: we sought to evaluate the long-term effects of alternative rightventricular pacing sites on myocardial funtion and perfusion. Metheods: We randomized 42 patients with complete atrioventricularblock(AVB)or sinus node dysfunction (SND) to undergo permanent ventricularstimulation either at the right ventricular apex (RVA )(n=18) or right ventricularinflow tract (RVIT) (n=24).All patients with normal cardiac function underwenttechnetium-99m gated single photon emission computed tomography(SPECT)and Multiple-gated equlibrium blood pool imaging(GBPI)before implantationof pacemake and at follow-up (3 month and 12 month ).The left ventricularejection fration(LVEF),globle LVEF,regional LVEF ,peak ventricular filling rateand myocardial perfusion imaging at different left ventricular wall werecollected by GBPI and SPECT. Results: After pacing, the mean QRS duration was significantly longerduring RVA pacing than during RVIT pacing (151±21vs.134±15ms,P=0.034).At three month ,the incidence of myocardial perfusion defects (50% vs. 25%)and regional wall motion abnormalities (45% vs. 25%) and LVEF (55±10% vs.55±15% ) were similar during RVA pacing and RVIT pacing(P>0.05) ,However, the peak ventricular filling rate was significantly lower during RVApacing than during RVIT pacing (1. 66±0.50 vs.2.37±0.64/s, P<0.01). At 12month, the incidence of myocardial perfusion defects (83% vs. 33%) andregional wall motion abnormalities (78% vs. 33%) were higher and LVEF (47±3vs. 56±1) was lower during RV A pacing than during RVIT pacing (all P<0.05),the peak ventricular filling rate was significantly lower during RVA pacing thanduring RVIT pacing (1. 66±0.16 vs.2.49±0.21/s, P<0.01). Patients with RVApacing had a significant increase in the incidence of myocardial perfusiondefects (P<0.05) and a decrease in LVEF (P<0.01) between 3 and 12 months,but patients with RVIT pacing did not (P>0.05).Conclusions: This study demonstrates that it is feasible on clinical thatusing tined fixed electrode pace at right ventricular inflow tract .what is more,this study also show that preserved synchronous ventricular activation withRVIT pacing prevents the long-term deleterious effects of RVA pacing onmyocardial perfusion and function in patients implanted with a permanentpacemaker.