Can strain rate imaging predict recovery of contraction after acute myocardial infarction?

To assess whether strain rate imaging (SRI) can serve to evaluate myocardial viability in patients with acute coronary syndrome (ACS).

In 23 patients with ACS, we measured longitudinal tissue Doppler strain and strain rate values from left ventricular basal, mid, and apical segments (n = 414). These segments were grouped according to their acute end-systolic strain values (S(ES)) into those with normocontraction (S(ES)≤-13%), hypocontraction (S(ES) between -13 and -7%), and severe contraction abnormality (S(ES)>-7%). At 8 months, we evaluated the recovery of contraction: Segments with acutely severe contraction abnormality that improved their strain values to ≤-7% were defined as viable, and those that failed to do so as non-viable. In the acute phase, S(ES), post-systolic strain, as well as systolic, early, and late diastolic strain rate values were significantly better in the viable than in the non-viable segments. Post-systolic strain had the best AUC 0.78, and a cut-off value of -3.8% predicted recovery from severe contraction abnormality with a sensitivity of 85% and specificity of 62%. The transmurality of the infarction, assessed by magnetic resonance imaging with delayed enhancement, was significantly larger in the non-viable than in the viable segments (P = 0.006). Acute global S(ES) and systolic strain rate showed the best correlations with final global S(ES) and global infarction percentage after recovery.

SRI can serve to evaluate myocardial viability in patients with ACS, and to assess the recovery of segmental as well as global left ventricular function.