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

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

Methods And Results: 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.

Conclusion: 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.