Quantification of Regional Myocardial Function following Acute Myocardial Infarction by Ultrasonic Strain Rate and Strain Imaging

Objectives: The rapid diagnosis and early risk stratification of patients presenting with acute myocardial infarction (AMI) is important. In experimental setting ultrasonic strain rate (SR) and strain (S) have been shown to identify changes in deformation predictive of ischemia. We sought to evaluate and compare regional myocardial function at “the risk zone” (ARZ) supplied by the culprit coronary artery (CCA) and at the remote (R) area during AMI (25 patients) and control zone (10 healthy subjects) using SR/S. Design and Methods: Longitudinal deformation (LD) was from the apical views to assess function in the septum (SW) and inferior (IW) walls. Both SW mid and apical segments were considered ARZ segment if the CCA was left anterior descending artery. IW and basal segments of the SW were ARZ, if CCA was the right coronary artery or left circumflex branch. Results: Segments were scored according to the standard wall motion score (WMS) and compared to the findings of SR/S imaging. The amplitude of peak systolic SR (pSR), maximal systolic S (pS), and overall maximal S (OS) were decreased in infarcted segments (p < 0.05 vs R, vs control (C)). The pS was lower than OS indicating that in many infarcted segments, maximal shortening was delayed and occurred during early diastole. Infarcted segments evaluated as having a WMS = 3 had a tendency to lower values of pS and OS (p < 0.05). Conclusions: The strain rate/strain magnitude and changes in time interval values reliably identify infarcted segments and differentiating those from remote zone segments. Longitudinal deformation parameters provided statistically significant additional information and allowed a rapid diagnosis of area and extent of myocardial infarction in this high risk group.