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Segmental wall motion dysfunction after acute myocardial infarction (AMI) has led to progressing left ventricular remodeling (LVR), which has gradually worsened cardiac function of AMI patients with poor prognosis. Our study sought to explore the prognostic value of speckle tracking imaging (STI) for LVR in AMI patients with the analysis of the relation between regional wall motion abnormality after AMI and LVR by STI in association with wall motion score index (WMSI).
83 patients with first onset AMI were enrolled from Jan 2012 to May 2015 and underwent echocardiography within 24hs of the infarcted onset (baseline) and at 6-month follow-up. LVR was defined as the percentage change of left ventricular end-diastolic volume (ΔLVEDV%) from baseline to 6-month follow-up was more than 20% (divided as LVR and non-LVR group). Standard long-axis and short-axis views were stored and analyzed for longitudinal (LS), radial (RS) and circumferential (CS) strain of STI metrics as well as scores of WMSI. Segments of WMSI≥2 were selected and calculated for the mean values of LS (LS_WMSI), RS (RS_WMSI) and CS (CS_WMSI).
LVR occurred in 27 AMI patients at 6-month follow-up. No difference has shown for demographics, electrocardiogram, lab tests, coronary angiography as well as the measurements of two-dimensional echocardiography between the two groups from baseline, while all STI metrics were found statistical difference for the comparisons (P＜0.05, all), especially the WMSI selected STI metrics (P＜0.001, all). Linear regression analysis demonstrated that CS_WMSI (r=0.716，P＜0.001) was the best correlated to ΔLVEDV% among all STI metrics and also the best predictor of LVR by receive operator curve analysis (sensitivity of 92.6%, specificity of 87.5% and area under the curve of 0.9563).
Baseline STI metrics precisely predicted LVR at 6-month follow-up. Among the STI metrics, CS_WMSI has shown preferable predictive and diagnostic value, which indicates the impairment of segmental circumferential wall motion is closely correlated to LVR after myocardial infarction.