Using Myocardial Strain in Acute Myocardial Infarction: a Clinical Case

Ischemic heart disease is the most common cause of death worldwide and its frequency is increasing. Myocardial infarction is one of the main causes of death in structure of cardiovascular mortality. Speckle-tracking echocardiography is the new modern important perspective ultrasound diagnostic method that allows determining myocardial deformation. This method is used to diagnose the myocardial ischemia and to evaluate the myocardial function and prognosis of cardiovascular diseases and it is also useful in selecting patients for cardiac resynchronization therapy. Speckle-tracking echocardiography is non-invasive, useful, actual and relatively fast implemented technique, that has high diagnostic value which does not depend on the angle of scanning as tissue doppler echocardiography, but it requires high training of doctor to detect and evaluate damaged myocardial area. Speckle tracking echocardiography allows assessing structural changes in the myocardium. It is based on tracking the separate acoustic markers' within the myocardium areas (speckles) trajectories in two-dimensional or three-dimensional gray-scale ultrasound image during the cardiac cycle. This method expends diagnostic capabilities of standard methods of investigation of patients with cardiovascular diseases, especially for patients with coronary artery lesions. Most studied parameter of speckle tracking echocardiography is global longitudinal strain that reflects function of subendocardial myocardial fibers, which are the most sensitive to the development of myocardial ischemia. Normal values of global longitudinal strain varied from −15.9% to −22.1% (mean −19.7%). Today the definition of the global longitudinal strain is added in the echocardiography standards. Early myocardial stretching and the presence of post-systolic peaks in investigated segments of left ventricle may indicate myocardial ischemia in damaged area. The decreasing parameters of the global longitudinal strain in the “bull's-eye” diagram makes possible to determine the infarct-related coronary artery. Flattened strain curve with low maximal value may indicate the presence of scar tissue. It may be useful for detecting patients with reduced blood flow who suffers from multi-vessel coronary lesion. Recent studies have proven that global longitudinal strain can be the predictor of major cardiac events (mortality from all causes, recurrent myocardial infarction, hospitalization due to acute heart failure, need for repeat revascularization, stroke, etc.) or pathological remodeling of the left ventricle, essential marker of negative prognosis. The trials demonstrate the evidence that reduced longitudinal segmental strain in the anterioseptal and inferior segments of left ventricular is independent predictor of the development of death, recurrent myocardial infarction or heart failure. Patients with myocardial infarction with decreased global longitudinal strain had higher risk for mortality, ventricular arrhythmias and heart failure. This article presents the clinical case of acute myocardial infarction, demonstrating the diagnostic value of using speckle-tracking echocardiography in clinical practice in addition to the standard diagnostic protocol as the method that may help to determine further tactics of diagnostics and treatment.