Introduction: Diagnosis and treatment of acute coronary syndrome without persistent ST-segment elevation (NSTEMI) remains a major challenge. A change in the concentration of cardiac enzymes indicates the possible existence of significant blood vessel stenosis and is often the main indication for emergency coronary angiography. A diagnostic method that would indicate the existence of stenosis of a particular coronary artery in this context would be of great help to the interventional cardiologist during coronary angiography and the patient himself would benefit from early revascularization. Aim: The aim of this study is to prove right echocardiographic assessment of myocardial ischemia a two-dimensional study of myocardial deformation (strain) with significantly higher sensitivity and specificity to revealing ischemia caused by stenosis of one or more coronary arteries compared to standard echocardiographic assessment of regional wall motion abnormalities (RWMA). Method: The study included 115 subjects with NSTEMI who had not previously been diagnosed with coronary heart disease, heart failure, structural heart disease, or had a left bundle branch block in the electrocardiogram during admission. All subjects underwent echocardiographic examination followed by coronary angiography. The examiner who did the coronary angiography had no insight into the echocardiography findings. In addition to classical echocardiography, echocardiographic analysis included DSDM during which regional and total myocardial strain and epicardial and endocardial strain of each segment were recorded. A total of 59 subjects had left anterior descendens or left main stenosis (LCA), 46 left circumflex artery stenosis (LCx), 44 right coronary artery stenosis (RCA), and 26 subjects did not have significant coronary artery stenosis. Anthropometric, laboratory and echocardiographic parameters were compared between subjects with and without stenosis and between subjects with coronary artery stenosis of interest and other subjects (with stenoses of other coronary arteries and those without coronary artery stenosis). Results: Numerous parameters of regional myocardial deformity were associated with stenosis of an individual blood vessel and they are correlated well with its supply area, while the same would not be concluded for any VIK parameter. Calcium channel blockers, hyperlipoproteinemia, higher diastolic pressure at admission, and medial anterior myocardial strain (LSMA) were independently associated with LCA stenosis (diagnostic accuracy of LSMA was 73.4%). Epicardial strain of the basal inferior segment was independently associated with the presence of RCA stenosis with diagnostic accuracy of 69%. Deformation of the basal posterior segment best predicted the existence of LCx stenosis with a diagnostic accuracy of 71.2%. Conclusion: A two-dimensional study of myocardial deformity has greater diagnostic accuracy versus RWMA in predicting the existence of NSTEMI.