Abstract 6120: Determinants of Left Ventricular Untwisting Behavior in Patients with Dilated Cardiomyopathy: Analysis by Two-Dimensional Speckle Tracking
Left ventricular (LV) untwisting velocity has emerged as a novel index of LV diastolic function since it is thought to be related to LV diastolic suction. However, the pathophysiology of LV untwisting behavior in the failing heart has not been fully investigated. The aim of this study was to investigate the determinants of left ventricular (LV) peak untwisting velocity in patients with dilated cardiomyopathy (DCM). One-hundred-one patients with DCM (mean age 60 ± 13 years) and 50 control subjects were evaluated. After a standard echocardiographic examination, peak torsion and peak untwisting velocity were measured using two-dimensional speckle tracking imaging (Vivid 7 Dimension, GE Healthcare). Radial dyssynchrony was assessed by speckle-tracking radial strain analysis. The patients with DCM had significantly smaller peak torsion (P < 0.001) and peak untwisting velocity (P < 0.001) and greater radial dyssynchrony (P < 0.001) compared with the control subjects. The peak untwisting velocity was correlated with end-systolic volume index (r = 0.524, P < 0.001), E/e′ (r = 0.365, P < 0.001), radial dyssynchrony (r = 0.578, P < 0.001), and peak torsion (r = −0.635, P < 0.001) in patients with DCM. Multivariate analysis revealed that peak torsion, radial dyssynchrony and E/e′ were independent predictors of peak untwisting velocity in patients with DCM (standard coefficient = −0.483, P < 0.001, 0.330, P < 0.001, and 0.241, P < 0.001, respectively). These results suggest that LV dyssynchrony and E/e′, a surrogate of LV filling pressure, as well as LV torsion are related to diastolic untwisting behavior in patients with DCM.