Evaluation of regional myocardial systolic function in the early stage of acute myocardial infarction by strain rate imaging

ABSTRACT

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. 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 [peak epsilon] and strain rate [SRs], end-systolic strain [epsilon es], post systolic shortening [PSS], time to peak systolic strain rate [tSRs], time to end of shortening [teSRs], post systolic strain [PS epsilon], post-systolic strain index [PSI], PSS ratio [PSS/ epsilon [Max]] and peak postsystolic strain rate [SRPSS]. There was not any association either between WMSI and ta [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 t epsilon epsilon 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 [a=0.056, P =0.70], PSI and teSRs [beta= -0.772, P=0.12]. Simple linear regression model showed a weak but significant relationship between PSI and Median t epsilon [beta = -0.851, P =0.04; r =0.33]. Our study showed that PCI resulted in early recovery of regional systolic function of infarcted myocardium during the early stage of acute myocardial infarction