Abstract 6121: Acute Effects of Cardiac Resynchronization Therapy on Left Ventricular Twist
Left ventricular (LV) twist is emerging as global and thorough parameter to define LV function. Aim of this study was to explore acute effects of CRT on LV twist in relation to LV lead position. A total of 80 heart failure (HF) patients and 30 normal controls were studied. Speckle tracking analysis of basal and apical short-axis echo images was performed to assess LV twist, at baseline and within 48 hours after CRT. LV response to CRT was defined as improvement of LVEF> 5%. At fluoroscopy, in the postero-anterior (PA) view, the distance between the coronary sinus/mitral ring plane and the cardiac apex was divided in 2 parts: mid-apical and mid-basal. At baseline HF patients (56 % ischemic) had mean LVEF of 26 ± 6%. Peak LV twist was severely depressed in HF patients compared to controls: 4.8 ± 2.6 vs. 15 ± 3.6° (p < 0.001). At baseline responders (54%) had significantly lower LV twist than non-responders and after CRT peak LV twist significantly improved in responders from 4 ± 2.4 to 7.7 ± 2.9°, p < 0.001, and worsened in non-responders from 5.7 ± 2.5 to 3.6 ± 1.9°, p < 0.001. The LV lead was placed in lateral or posterolateral vein in 93% patients. From the PA view 41 HF patients had mid-apical LV lead and 39 mid-basal LV lead. LV twist significantly improved in mid-apical and worsened in mid-basal LV lead group (Δ LV twist 3.6 ± 2.7° vs. −1.7 ± 2.5°, p < 0.001). Furthermore, mid-apical position of LV lead was associated with high prevalence of acute responders (86%). Acute response to CRT is associated with significant improvement of LV twist. A greater improvement of LV twist and ejection fraction was observed when LV lead was placed in a target vein in mid-apical position.