Abstract 17645: Reduced Subendocardial Longitudinal Myocardial Strain by 2-Dimensional Speckle Tracking Echocardiography in Patients with Coronary Artery Disease: Comparative Study with Late Gadolinium Enhanced Magnetic Resonance Imaging

Abstract

Background: Subendocardial (inner-) myocardial layer is more sensitive to the myocardial ischemia than subepicardial (outer-) layer. Novel developed software for 2D speckle tracking imaging (2D STE) allows measurement of inner- and outer- myocardial strain separately. Late gadolinium enhanced magnetic resonance imaging (LGE MRI) can accurately delineate the myocardial infarction (MI) with high spatial resolution. In the current study, we assessed the hypothesis that inner-strain was more impaired than outer-strain in the segments with MI on LGE MRI.

Methods: Twenty patients (mean age: 68± 9 years, men: n=17) with known or suspected coronary artery disease (CAD) were enrolled. Inner- and outer- myocardial peak longitudinal strain was assessed in the apical long-axis, two- and four-chamber views by using an echocaridiographic 2D speckle tracking software. All patients underwent LGE MRI to evaluate the presence or absence of MI. Myocardial segments were divided into two groups based on the presence or absence of MI on LGE MRI: segments without MI on LGE MRI, segments with MI on LGE MRI. Myocardial strains were compared between two groups by using unpaired t test.

Results: On LGE MRI, myocardial infarction was observed in 88 of 360 (24.4%) segments. Mean left ventricular ejection fraction was 49.1± 16.1% on echocardiography.Myocardial strain measurement was feasible in 339 of 360 (94%) segments. In the segments with LGE, inner-strain was significantly smaller than those without LGE (-7.5 ± 3.5 vs -9.7 ± 4.2, p<0.001). However, outer-strain was similar in both groups (-6.4 ± 3.0 vs -7.0 ± 3.7, p=0.24). Inner/outer strain ratio was significantly decreased in the segments with MI than those without MI (1.23 ± 0.39 vs 1.64 ± 1.15, p=0.003).

Conclusion: Subendcardial longitudinal strain and inner/outer strain ratio were significantly impaired in the segments with MI in comparison to those without. The results in the current study indicate that both myocardial longitudinal strain in subendorcardial layer and inner/outer strain ratio by 2D STE might be useful indices for non-invasive detection of myocardial infarction.