Recovery of Function After Acute Myocardial Infarction Evaluated by Tissue Doppler Strain and Strain Rate

Background

The aim of this study was to investigate the changes and time course of recovery of regional myocardial function within the first week following successful primary coronary intervention in patients with first-time ST-segment elevation myocardial infarctions using myocardial deformation analysis, which is more quantitative and thus more objective than the wall motion score.

Methods

Thirty-one consecutive patients admitted with ST-segment elevation myocardial infarctions were studied on days 1, 2, 3, and 7 using strain and strain rate tissue Doppler echocardiography.

Results

The mean peak troponin T level was 7.0 μg/L, and 15 patients had anterior and 16 had inferior infarct localization. Peak systolic strain rate and end-systolic strain increased significantly on day 2, both in segments with moderately reduced function (−0.6 to −1.0 s⁻¹ vs −8% to −15%, P < .001) and in severely reduced function (−0.2 to −1.0 s⁻¹ vs 1% to −12%, P < .001), but there were no further changes. Mean wall motion score in infarct related segments decreased significantly from day 1 to day 2 (2.7 to 2.4, P = .001) and from day 3 to day 7 (2.3 to 2.2, P = .001).

Conclusions

Recovery of regional function after ST-segment elevation myocardial infarction occurred within 2 days and could be detected by wall motion score, strain rate, and strain. However, strain and strain rate were better discriminative parameters for the changes in function as well as being better to assess near normalization on day 2. This could have a clinical impact on early management in patients who undergo percutaneous coronary intervention.

Keywords: Strain rate, Strain, Strain rate imaging, Tissue Doppler, Acute myocardial infarction, Echocardiography