Speckle tracking echocardiography derived systolic longitudinal strain is better than rest single photon emission tomography perfusion imaging for nonviable myocardium identification

Abstract

Background. The aim was to compare the speckle tracking echocardiography (STE) derived systolic longitudinal strain (SLSmax) with rest single photon emission computed tomography (SPECT) perfusion imaging (QREST), and to define the optimal cut-offs for SLSmax to discriminate transmural scar on contrast-enhanced magnetic resonance imaging (ceCMR). Methods and Results. In 100 patients with chronic ischemic left ventricular (LV) dysfunction, myocardial viability was assessed using STE and rest SPECT to predict LV segmental relative extent of delayed enhancement (DE) >75% on ceCMR. Correlation was found between regional SLSmax (r=-0.59, P<0.0001) and DE on ceCMR. The SLSmax optimal cutoff -5.3% identified segments with DE>75% on ceCMR (sensitivity 83.1%, specificity 84.6%). Optimal cut-offs SLSmax for segments corresponding to individual perfusion territories (-3.6%, -5.3% and -4.7% for LAD, LCx resp. RCA perfusion territories) were identified. There was a significant difference (AUC 0.866 vs. 0.822 for SLSmax resp. QREST, p=0.036) in the accuracy of predicting non-viable segment due to the greater accuracy of SLSmax than QREST in the RCA perfusion territory (AUC 0.893 vs. 0.75 for SLSmax resp. QREST, P=0.001). Conclusions. STE enabled identification of LV non-viable segments. Cut-off values derived for perfusion territories of individual coronary arteries improve the accuracy of predicting a transmural scar presence. In comparison with rest myocardial SPECT perfusion imaging, STE is more accurate in predicting non-viable myocardium.