Evaluation of Regional Myocardial Systolic Function in the Early Stage of Acute Myocardial Infarction by Strain Rate Imaging

Abstract

Background: We sought to evaluate the impact of different therapeutic strategies on longitudinal regional myocardial systolic function in the early phase of acute myocardial infarction using strain rate imaging.Methods: A total of 38 patients (34 males), with first acute myocardial infarction (AMI) were evaluated. Our patients were divided into 3 groups according to the kind of therapy. The mean age of the patients was 55 ± 9.4 years (range: 39- 75 years). Mean left ventricular ejection fraction (LVEF) in the patients was 41 ± 10.7%. Primary percutaneous coronary intervention (PCI) was performed in 10 patients. Sixteen patients were treated by thrombolytic therapy using streptokinase (SK) and 12 were followed-up conservatively. All patients underwent a comprehensive echocardiography study including SR imaging within 3- 5 days after AMI. The parameters measured included peak systolic strain (peakε) and strain rate (SRs), end-systolic strain (εes), post systolic shortening (PSS), time to peak systolic strain rate (tSRs), time to end of shortening (teSRs), post systolic strain (PSε), post-systolic strain index (PSI), PSS ratio (PSS/ εMax ) and peak postsystolic strain rate (SRPSS).Results: There was not any association either between WMSI and tå (P=0.4), or MI location and PSS ratio (P=0.13). But there was an inverse relationship between WMSI and mean SRS, especially when WMSI was more pronounced. A significant relationship was found between tε and teSRs with the kind of therapy (shorter in PCI group (P= 0.04). Using a simple linear regression model, no association was found between PSS ratio and SRs (â=0.056, P =0.70), PSI and teSRs (β= -0.772, P =0.12). Simple linear regression model showed a weak but significant relationship between PSI and Median tε (β = -0.851, P = 0.04; r =0.33).Conclusion: Our study showed that PCI resulted in early recovery of regional systolic function of infarcted myocardium during the early stage of acute myocardial infarction.