Objective: This study was conducted to evaluate the relationship between ST segment resolution and left ventricular performance as well as other clinical parameters after thrombolytic therapy in cases of acute ST segment elevation myocardial infarction. Patients and methods: This study included 80 patients presenting with acute ST elevation myocardial infarction (STEMI) and designed for intravenous thrombolytic therapy (Tenecteplase). Patients were classified into two groups; group 1 included 60 patients who showed < 50% ST segment resolution, and group 2 included 20 patients, who showed ~ 50% ST segment resolution. All patients were subjected to thorough history taking, full clinical examination, ,ECG before and 90 minutes after initiation of thrombolytic therapy then daily till discharge and routine laboratory Investigations. Also, all patients underwent acute (l: 2 days) & pre discharge (6:7 days) echocardiographic examination. Results: In group (1) involving patients with < 50 % ST segment resolution the mean age was significantly higher compared to group (2) which involves patients with >50% ST segment resolution (69 ± 11.3 vs. 58.5 ± 10.5 ) p-value