New Noninvasive Method for Assessment of Left Ventricular Rotation: Speckle Tracking Echocardiography

Background-: Left ventricular (LV) torsion is due to oppositely directed apical and basal rotation and has been proposed as a sensitive marker of LV function. In the present study, we introduce and validate speckle tracking echocardiography (STE) as a method for assessment of LV rotation and torsion. Methods and Results-: Apical and basal rotation by STE was measured from short-axis images by automatic frame-to-frame tracking of gray-scale speckle patterns. Rotation was calculated as the average angular displacement of 9 regions relative to the center of a best-fit circle through the same regions. As reference methods we used sonomicrometry in anesthetized dogs during baseline, dobutamine infusion, and apical ischemia, and magnetic resonance imaging (MRI) tagging in healthy humans. In dogs, the mean peak apical rotation was -3.7+/-1.2[degrees] (+/-SD) and -4.1+/-1.2[degrees], and basal rotation was 1.9+/-1.5[degrees] and 2.0+/-1.2[degrees] by sonomicrometry and STE, respectively. Rotations by both methods increased (P