Utility of Two-Dimensional Speckle Tracking Echocardiography in Understanding of Inferior ST Segment Depression in the Setting of Acute Anterior Myocardial Infarction
Background: A patient suffering from an anterior ST segment elevation myocardial infarction (STEMI) will frequently demonstrate ST segment depression (STD) in the inferior leads (II, III, and aVF). The aim of this study was to determine the meaning of STD in the early stages of an acute anterior MI, and whether they represent remote ischemia or reflect an electrical mechanism by using speckle-tracking echocardiography.
Methods: Fifty patients suffering from acute anterior STEMI were enrolled in this prospective study. The patients were classified into two groups each one included 25 patients. Group 1 included patients who had STD in the inferior leads and group 2 included patients who had not. All of the patients were evaluated with a standard 12-lead electrocardiography (ECG), two dimensional echocardiography, speckle-tracking echocardiography, and coronary angiography.
Results: The average global longitudinal peak systolic strain (Avg_GLPS%) was - 9.8 ± 2.4% in group 1 versus -10.7 ± 2.3 in group 2 (p=0.188). The longitudinal strains of the basal inferior segments were -13.6 ± 2.8% in group 1 versus -15.8 ± 3.7% in group 2 (p=0.026), and the longitudinal strains of mid inferior segments were -13 ± 3.2 in group 1 versus -15.1 ± 2.7% in group 2 (p=0.019). Group 1 had higher frequency of multivessel disease, right coronary artery (RCA) and left circumflex coronary artery (LCX) stenosis than group 2.
Conclusion: This study supports the belief that inferior STD on an ECG during an acute anterior STEMI is a sign of ischemia that often involves the right coronary artery.