Strain Rate Imaging Differentiates Transmural From Non-Transmural Myocardial Infarction: A Validation Study Using Delayed-Enhancement Magnetic Resonance Imaging

Objectives: The aim of this study was to determine if strain rate imaging (SRI) correlates with the transmural extent of myocardial infarction (MI) measured by contrast-enhanced magnetic resonance imaging (Ce-MRI). Background: Identification of the transmural extent of myocardial necrosis and degree of non-viability after acute MI is clinically important. Methods: Tissue Doppler echocardiography with SRI and Ce-MRI were performed in 47 consecutive patients with a first acute MI between days 2 and 6 and compared to 60 age-matched healthy volunteers. Peak myocardial velocities and peak myocardial deformation strain rates were measured. Location and size of the infarct zone was confirmed by Ce-MRI using the delayed enhancement technique with a 16-segment model. Results: Contrast-enhanced MRI identified transmural infarction in 21 patients, non-transmural infarction in 15 (mean transmurality of infarct 72.3 ± 10.6%), and another 11 patients with subendocardial infarction (<50% transmural extent of the left ventricular wall). Peak systolic strain rate (SRs) of the transmural infarction segments was significantly lower compared to normal myocardium or with non-transmural infarction segments (both p < 0.0005). A cutoff value of SRs >−0.59 s−1 detected a transmural infarction with high sensitivity (90.9%) and high specificity (96.4%), and −0.98 s−1 >SRs >−1.26 s−1 distinguished subendocardial infarction from normal myocardium with a sensitivity of 81.3% and a specificity of 83.3%. Conclusions: Peak myocardial deformation by SRI can differentiate transmural from non-transmural MI, and it allows noninvasive determination of transmurality of the scar after MI and thereby the extent of non-viable myocardium. [Copyright &y& Elsevier]