Abstract 3053: Left Ventricular Apical Rotation, but Not Basal Rotation Contributes to Twist in Normal Subjects: Evaluation by a Novel Automated Three-Dimensional-Wall Motion Tracking Technique
Background: Left ventricular (LV) rotation and twist have assessed by two-dimensional speckle tracking (2D-T), however, “through-plane phenomenon” has been unavoidable limitation for evaluating LV rotation by 2D-T. To overcome this effect, we evaluated apical and basal rotation by newly developed three-dimensional-wall motion tracking (3D-T).
Methods: Three-dimensional volume data sets were acquired from apex (Artida, Toshiba Medical Systems) in 20 healthy subjects. Thirty-five short axes (SAX) plane which were parallel to basal SAX plane and 36 tracking points at 10 degree intervals around each SAX were defined in the endocardium. Total 1261 points (35 planes with 36 points per plane plus the apex) were tracked during a cardiac cycle. Apical and basal planes defined at end-diastole and rotation angle in each plane was obtained by 3D-T. Two-dimensional apical and basal SAX views were recorded and their rotation angles were evaluated by 2D-T. LV twist was defined as a difference between the apical and basal rotation.
Results: Apical rotation angles by 3D-T were greater than those by 2D-T (11.0±5.4 vs 6.9±3.0°, p<0.01). In contrast, basal rotation angles were significantly smaller compared with those by 2D-T (−1.3±2.1 vs −4.9±2.6°, p<0.01). Twist angles were similar in both methods.
Conclusion: The behaviors of LV apical and basal rotation during cardiac cycle evaluated by 3D-T differed from those by 2D-T. The 3D-T revealed the apical rotation represents the dominant contribution to LV twist in healthy subjects.