Abstract 2243: Differentiation Between Transmural and Non-Transmural Infarction by Assessment of Circumferential Strain by Speckle Tracking Echocardiography
Background: Differentiation between transmural (non-viable) and non-transmural (viable) myocardial infarction (MI) is of clinical importance. Speckle tracking echocardiography (STE) has recently been introduced as an angle independent method for assessment of regional myocardial function. Since the transmural distribution of LV myocardial fibers is mainly circumferential, we hypothesized that the reduction in circumferential strain (strainc) in an infarcted segment measured by STE, would correlate with the degree of scarring of the segment.
Methods: In 10 patients with chronic LAD related MI, LV apical short-axis recordings were obtained by 2-D echocardiography and by MRI tagging. MI size was assessed by late gadolinium enhancement technique, and for each patient the MI was divided into homogenous segments of >50% and/or <50% MI. Peak negative systolic strainc (end-systolic strainc in segments of systolic lengthening) was measured in the corresponding and non-infarcted segments by both speckle tracking and tagging analyses.
Results: Segmental strainc measured by STE and MRI demonstrated good correlation and agreement (r=0.79, P<0.001, meanΔ±SD=0.5±5.3%). Segmental strainc by STE differed significantly between segments of 0, <50 and >50% MI (−23.5±3.4, −12.6±2.1 and −4.3±5.9, respectively, P<0.001, Figure 1⇓), and showed excellent correlation with segmental MI size (r=0.93, P<0.0001, Figure 2⇓). A strainc cutoff value of −10.5% detected transmural MI (>50%) with high sensitivity (94%) and specificity (100%).
Conclusions: Strainc can be measured accurately by STE and may differentiate between transmural and non-transmural MI.