Background. Infarct size is an important factor affecting left ventricular contractility, function, in-hospital and long-term prognosis. At present, there is no method available that would allow to assess post-infarction necrotic zone size in an easy manner.Aim. To create a mathematical formula which would allow to estimate infarct size and post-infarct remodelling of left ventricle.Material and methods. 120 patients with first, acute ST-elevation myocardial infarction undergoing primary coronary angioplasty were included in the study. Each of these patients had routine laboratory, angiographic and clinical parameters measured, and serial assessments of necrotic marker levels and ECG were performed. Based on magnetic resonance results, infarct size, ejection fraction and remodelling parameters were obtained.Results. Based on obtained data, a linear regression formula was created that enables to estimate infarct zone and post-infarction left ventricular ejection fraction. Unfortunately, attempts to create a model to estimate post-infarction remodelling were not successful.