Abstract 2075: Evaluation of Left Ventricular Relaxation Using Untwisting Rate by Speckle Tracking Echocardiography
Background: LV untwisting rate (UTR) has been shown to reflect LV relaxation in animal studies. The goal of this study was to investigate the value of UTR assessed by 2D speckle tracking for evaluation of LV diastolic function in human subjects.
Methods: Sixty seven patients (57±17 years, 19 women) in sinus rhythm were studied with echocardiography simultaneously with right heart catheterization. Twenty healthy subjects were included as a control group. In addition to conventional variables for functional analysis, apical and basal rotations were measured using 2D speckle tracking from 2D LV cross-sectional loops at the apical and basal levels. LV twist was calculated as the difference of apical and basal rotations. UTR was derived as the peak negative diastolic time derivative of twist.
Results: Among the 67 patients, 34 had ejection fraction (EF) <50% (25±9%)(SHF group), and 33 had normal EF (64±7%) and diastolic dysfunction (DHF group). SHF patients had a significantly lower UTR (−55 °/s) than controls (−89 °/s) and DHF patients (−104 °/s, p<0.05). UTR was similar in DHF patients and controls (P>0.05). In general, UTR was significantly related to τ (r=−0.65, P<0.001), mean wedge pressure (r=−0.39, P=0.003), LV end diastolic (r=−0.50, P<0.001), end systolic volume (r=−0.58, P<0.001), and EF (r=0.7, P<0.001). Subsequently, the analysis was performed separately in SHF and DHF patients. UTR was significantly related to τ in SHF patients (r=−0.78, P<0.001), but not in DHF patients (r=0.29, P=0.15).
Conclusion: LV UTR is reduced in patients with depressed EF, but not in those with normal EF. The preserved LV UTR in the latter group may be a compensatory mechanism that aids LV filling.