Abstract 2923: AV and VV Optimization Causes Incremental Improvement in Cardiac Output and Synchrony Post Cardiac Resynchronization Treatment
BACKGROUND: Cardiac resynchronization treatment (CRT) causes improvement in cardiac function and synchrony in heart failure. The aim of this study was to determine whether echo-guided atrioventricular optimization (AVO) and optimization of V-V timing (VVO) of biventricular (Biv) pacemaker would cause incremental improvement in cardiac output and cardiac synchrony post CRT.
METHODS: 23 pts, 65 ± 16 yrs, 78% M, 61% ischemic cardiomyopathy, 26% with LBBB, underwent CRT and then AVO and VVO 21 ± 29 days post CRT. 20 had percutaneous CRT (left ventricular (LV) lead in the posterolateral vein in 15 and in anterolateral vein in 5) and 3 had epicardial CRT. Nominal and 6 VV delays and 50–250 ms AV delays were tested in each pt. Optimal AV and VV delay was determined from the AV and VV interval corresponding to the maximum aortic velocity time interval (VTI) by pulsed wave (PW) Doppler. Tissue Doppler imaging (TDI) in the apical 4, 2 and 3 chamber views was performed pre CRT, post CRT, post AVO and post VVO using GE vivid 7 ultrasound system. Ejection septolateral delay, asynchrony index [standard deviation of time to peak systolic velocity (PSV) during aortic ejection in 12 LV segments], maximum difference in time to PSV in 12 LV segments during entire cardiac cycle, and septoposterior wall delay (SPWD) during ejection & post ejection phase were measured as criteria of mechanical asynchrony.
RESULTS: LV ejection fraction improved from 26 ± 8% to 31 ± 7% and NYHA class from 3.4 ± 0.9 to 1.94 ± 0.6 (p < 0.01 pre vs post CRT for both). Table⇓ shows echo and TDI parameters pre and post CRT, post AVO and post VVO. #p < 0.05 vs. AVO, **p < 0.05 vs baseline. AV delay was 120 ± 15 ms pre and 150 ± 45 ms post AVO. Mean VV delay was LV ist by 15 ± 20 ms post VVO. Nominal VV delay was optimal in 17%, LV ist in 60% and RV ist in 13% of pts.
CONCLUSIONS: Optimization of atrioventricular and interventricular interval of Biv pacemaker by evaluation of PW aortic VTI causes incremental improvement in cardiac output and LV synchrony in pts post CRT./>