Abstract 15845: Assessment of Myocardial Ischemic Memory Using 3-Dimensional Speckle Tracking Echocardiography

Abstract

Background: Post-systolic shortening (PSS), which is defined as myocardial contraction after aortic valve closure (AVC), is a sensitive marker of ischemia and remains even after restoration of perfusion (myocardial ischemic memory). The newly developed 3-dimensional (3D) speckle tracking imaging allows to quantitatively analyze regional wall motion of the entire left ventricle and is useful for the diagnosis of ischemic heart disease. However, because the frame rate (FR) of 3D imaging is lower than the 2-dimensional method, it is unknown whether assessment of ischemic memory using persistence of PSS is possible.

Methods: The left circumflex coronary artery was occluded for 2 minutes followed by 60-minute reperfusion in 9 dogs. Three-dimensional images were acquired at baseline, during occlusion and after reperfusion at 3 different FR settings (21.5, 38.2, 48.2 frames/s) using Vivid E9 (GE). Radial, circumferential, longitudinal, and area strain were calculated in the risk and normal areas. With each direction, peak systolic strain (ε_sys) and post-systolic index (PSI) as a parameter of PSS were measured.

Results: In the risk area, ε_sys decreased during occlusion but recovered immediately after reperfusion regardless of FR. With the highest FR 48.2 frames/s, PSS was clearly observed in the risk area during occlusion and PSI increased compared to that at baseline. The increase of PSI significantly persisted even 20 minutes after reperfusion (baseline vs. 20-minute after reperfusion: area strain; 0.02±0.03 vs. 0.07±0.09, circumferential strain; 0.02±0.04 vs. 0.12±0.12, p<0.05). In longitudinal and radial strain, the increase of PSI also tended to persist after reperfusion. With 21.5 and 38.2 frames/s, PSI increased during occlusion; however, it was difficult to detect the residual PSS 20 minutes after reperfusion in all directions (Figure).

Conclusion: 3D speckle tracking echocardiography can assess ischemic memory using high FR.