Abstract 14069: Feasibility of Assessment of Regional Function Using Wall Tension - Area Strain Loop Derived From Three-Dimensional Speckle Tracking Echocardiography
Background: Recent advancement of three-dimensional (3D) speckle tracking echocardiography enables us to assess area strain as well as circumferential, radial and longitudinal strains. Area strain shows percent change of the pre-defined area on the endocardial layer during a cardiac cycle and is considered to be robust in assessing regional function. We investigated the feasibility of wall tension-area strain (T-AS) loops to assess regional function in the dog myocardial ischemia model.
Methods: Three-dimensional full volume images were acquired using 3D echocardiography (Aplio Artida™, Toshiba) before and during brief occlusion of the left circumflex coronary artery in 8 dogs. Left ventricular (LV) pressure (P) was simultaneously recorded by a micromanometer-tipped catheter (Millar). LV short axis diameter (D) at the basal level and area strain were measured in the risk and normal areas. Wall tension (T) was calculated according to Laplace's law for a spherical model as T = DP / 4. T-AS loop was constructed during one cardiac cycle. We calculated the ratio of wall tension to the area strain in end-systole as an index of regional function (slope of T-AS loop).
Results: During coronary occlusion, the T-AS loop shifted rightward for the risk area while unchanged for the normal area. The slope of T-AS loop for the risk area was increased significantly and that for the normal area was not changed (before vs. during occlusion; −4.55 ± 2.20 vs. −54.4 ± 108 mmHg·cm·%−1, p = 0.001 for the risk area, −2.78 ± 1.15 vs. −2.45 ± 1.08 mmHg·cm·%−1, p=NS for the normal area, Figure).
Conclusions: The wall tension — area strain loop well reflected regional dysfunction caused by myocardial ischemia. This analysis using 3D speckle tracking echocardiography may be useful to quantify regional function.
- © 2010 by American Heart Association, Inc.