Background: The aim was to compare the speckle tracking echocardiography (STE) derived systolic longitudinal strain (SL(Smax)) with rest single photon emission computed tomography (SPECT) perfusion imaging (Q(REST)), and to define the optimal cut-offs for SL(Smax) 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 SL(Smax) (r=-0.59, P<0.0001) and DE on ceCMR. The SL(Smax) optimal cut-off -5.3% identified segments with DE>75% on ceCMR (sensitivity 83.1%, specificity 84.6%). Optimal cut-offs SL(Smax) 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 SL(Smax) resp. Q(REST), p=0.036) in the accuracy of predicting non-viable segment due to the greater accuracy of SL(Smax) than Q(REST) in the RCA perfusion territory (AUC 0.893 vs. 0.75 for SLSmax resp. Q(REST), 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.