B-PO03-190 COMPARISON OF ADAPTIVE AND NON-ADAPTIVE PACING MODES WITH BIVENTRICULAR STIMULATION ON TIME-TO-PEAK DERIVATIVE OF LEFT VENTRICULAR PRESSURE

Abstract

Time-to-peak dP/dt (Td) is marker of mechanical resynchronization. Td links the time domain (dyssynchrony) to the mechanical domain (pressure) as the dyssynergic muscular contractions resulting from electrical dyssynchrony delays pressure development and hence the timing Td. Td shortens with resynchronization. In this study we investigated the acute changes in Td with standard BIVP and fusion with intrinsic conduction, single or multiple LV electrodes and different VV-intervals. 19 patients with sinus rhythm and LBBB undergoing CRT implantation were studied. We measured pressures with an indwelling LV pressure sensor catheter. Td was calculated as the time from onset of pacing to peak dP/dt and averaged in 10 subsequent beats at each stage of pacing. We used quadripolar LV pacing leads positioned in what was considered an optimal mid/basal posterolateral/ lateral branch of the coronary sinus and sequential pacing (DDD) was performed; Adaptive (A) and Non-Adaptive (NA) BIVP was performed at LV distal [LVdist], proximal electrode [LVprox] and at both electrodes as multipoint pacing [MPP]. VV-timing: LV pacing was performed relative to QRS onset (either as a result of intrinsic activation or RV pace, mean±SD): 1. LV only 76±21ms before QRS activation with minimal fusion with RV activation (LVonly); 2. 28±14ms before QRS activation (Pre); 3. 12±15ms after (Post) QRS activation. Average Td (data pooled) with RVP was 173±2ms, MPP 144±0.4ms and BIVP 150±0.4ms. Analyzing pacingmode (A,NA), VV-timing (LVonly,Pre,Post) and electrode (LVdist,LVprox,MPP) we found that Td was shorter (p<0.01) with A(Post) for all electrode combinations [LVdist] 143±4ms, [LVprox] 140±4ms and [MPP] 134±4ms, while Td with A(Pre) was shorter with [MPP] 139±4ms only. NA(Post)[MPP] at 145±4ms and NA(Post)[LVdist] at 146±4ms provided the shortest Td (p<0.01) of the NA pacing modes, and Td with NA(Post)[MPP] was shorter (p<0.01) than all NA pacing modes. A(post)[MPP] provided the shortest Td of all (134±4ms, p<0.01). Td shortens the most with LV MPP timed to near simultaneous intrinsic RV activation, indicating a beneficial mechanical effect from Adaptive MPP compared to standard biventricular pacing modes.