Does RV lead positioning provide additional benefit to cardiac resynchronization therapy in patients with advanced heart failure?

Background and Objectives: The left ventricular (LV) stimulation site is currently recommended to position the lead at the lateral wall. However, little is known as to whether right ventricular (RV) lead positioning is also important for cardiac resynchronization therapy. This study compared the acute hemodynamic response to biventricular pacing (BiV) at two different RV stimulation sites: RV high septum (RVHS) and RV apex (RVA). Methods and Results: Using micro-manometer-tipped catheter, LV pressure was measured during BiV pacing at RV (RVA or RVHS) and LV free wall in 33 patients. Changes in LV dP/dt_max and dP/dt_min from baseline were compared between RVA and RVHS. BiV pacing increased dP/dt_max by 30.3 ± 1.2% in RVHS and by 33.3 ± 1.7% in RVA (P = n.s.), and decreased dP/dt _min by 11.4 ± 0.7% in RVHS and by 13.0 ± 1.0% in RVA (P = n.s.). To explore the optimal combination of RV and LV stimulation sites, we assessed separately the role of RV positioning with LV pacing at anterolateral (AL), lateral (LAT), or posterolateral (PL) segment. When the LV was paced at AL or LAT, the increase in dP/dt_max with RVHS pacing was smaller than that with RVA pacing (AL: 12.2 ± 2.2% vs 19.3 ± 2.1%, P < 0.05; LAT: 22.0 ± 2.7% vs 28.5 ± 2.2%, P < 0.05). There was no difference in dP/dt_min between RVHS- and RVA pacing in individual LV segments. Conclusions: RVHS stimulation has no overall advantage as an alternative stimulation site for RVA during BiV pacing. RVHS was equivalent with RVA in combination with the PL LV site, while RVA was superior to RVHS in combination with AL or LAT LV site.