Abstract 3044: Immediate Improvemement of Subepicardial Left Ventricular Twist Predicts Clinical and Echocardiographic Response to Cardiac Resynchronization Therapy
Introduction. Left ventricular (LV) twist is the result of the simultaneous wringing motion of the subepi- and subendocardial layer and is emerging as comprehensive index of LV systolic function. Subepicardial layer leads the direction of LV twist, having larger radius of rotation. Furthermore, LV rotational mechanics is strongly influenced by electro-mechanical activation. The aim of the study was to explore whether the immediate changes (Δ) of LV twist in both layers induced by cardiac resynchronization therapy (CRT) were related to clinical and echocardiographic response at 6 months follow-up.
Methods. A total of 78 HF patients undergone CRT were included. Real-time three-dimensional echocardiography was performed in the overall study population and repeated within 48 hours and after 6 months follow-up, to assess LV volumes, LV ejection fraction (EF) and systolic dyssynchrony index (SDI). Speckle tracking analysis was applied to LV basal and apical short axis images to assess apical and basal rotation in subepi- and subendocardial layer. LV twist was defined as the net difference at isochronal time point between apical and basal rotation. Response to CRT was based on clinical and echocardiographic criteria (improvement >1 New York Heart Association functional class + absolute improvement of LVEF≥5%).
Results. The mean age was 66±10 years, 51 men. Ischemic aetiology of HF was present in 40 (51%) patients. At baseline LVEF was 26±6%, SDI was 8.1±2.6%, peak subepicardial LV twist was 2.1±1.8° and peak subendocardial LV twist was 4.2±3.1°. Responders to CRT (n=44, 56%) had an immediate improvement of SDI (from 8.9±2.6% to 5.5±1.9%, p<0.001), subepi (from 1.2±1.6° to 3.9±2.3°, p<0.001) and subendocardial LV twist (from 3.3±2.9° to 5.6±3.2°, p<0.001) after CRT. After analyzing all clinical and echocardiographic variables (ischemic etiology, QRS duration, ΔLV end-systolic volume, Δ SDI, Δ subendocardial LV twist), Ä subepicardial LV twist was the strongest predictor of CRT response at 6 month follow-up (odds ratio 3.6, 95%confidence intervals 1.6 – 8.1, p=0.002).
Conclusions. An immediate improvement of subepicardial LV twist predicts clinical and echocardiographic CRT response at 6 months follow-up.