Background: Despite advances in the diagnosis, prognosis and treatment with new approaches, STEMI remains the most common cause of cardiovascular mortality and morbidity in developing countries.Aim of the work: The aim of the work was to investigate clinical characteristics of patients with fragmented QRS and QRS distortion to determine if they can help to identify high risk STEMI patients and to determine whether they can be used as non-invasive markers to predict response to reperfusion therapy. Methods: The present study conducted on 150 patients who were admitted to Cardiology Department, Zagazig University, from July 2018 to December 2018, with acute STEMI and treated with thrombolytic and/or primary PCI. University, from July 2018 to December 2018, 150 p.t were selected. Patients were divided into 4 groups; Group 1: included patients with 15 patients, Group 2: included 36 patients with QRS distortion, Group 3: included 84 patients with fQRS and QRS distortion and Group 4: included 15 patients without FQRS or QRS distortion. Results:  The present study showed no statistical significant difference between the four groups as regard to age and sex, hypertension, diabetes mellitus, smoking, dyslipideamia and family history of coronary artery disease and a significant statistical difference between patients with lateral MI, fQRS before and after reperfusion and QRS distortion before and after reperfusion and a highly significant statistical difference between different groups regarding EF and WMSI.. Conclusions: fQRS and QRS distortion can be used for assessment of success of reperfusion therapy.