Objectives: The objective of the present study was to investigate the ability of strain by Doppler and by speckle tracking echocardiography in the acute phase in patients with ST-segment elevation myocardial infarction (STEMI) to diagnose left ventricular (LV) infarct size. Furthermore, we wanted to study at which time during the cardiac cycle strain should be measured.
Background: The assessment of regional myocardial dysfunction may be an important diagnostic tool in the evaluation of acute myocardial injury.
Methods: Strain by Doppler and speckle tracking were assessed in the acute phase and after 10 days in 36 patients (61 +/- 11 years) with STEMI treated with thrombolysis. In a 16-segment model of the LV, peak systolic, end systolic, and peak negative strain were validated against the corresponding myocardial segments measured by contrast-enhanced cardiac magnetic resonance. The 16 segments were averaged to assess LV global longitudinal strain. In addition, 6 segments were analyzed from parasternal short-axis recordings at the papillary muscle level to assess circumferential strain. Reproducibility was tested in 20 patients.
Results: The different segmental strain assessments separated significantly (p < 0.0001) between the different levels of infarct transmurality regardless of method, with better reproducibility for speckle strain. Circumferential strain separated better than longitudinal strain. With a cutoff value of -13.3% for segmental circumferential strain, sensitivity was 80% and specificity was 74% for prediction of transmural infarction. The LV global strain showed a good correlation with LV infarct size, with the best correlation for LV global peak systolic speckle strain (beta = 0.76, p < 0.0001).
Conclusions: On a segmental level, circumferential strain separated transmural from subendocardial necrosis better than longitudinal strain in the acute phase in patients with STEMI. Our findings suggest that in the acute phase in patients treated with thrombolysis, LV global peak systolic speckle strain should be the preferred method for predicting final LV infarct size.