Background: Left ventricular (LV) dysfunction is the single most accurate predictor of death and one of the most common and lethal consequences after ST segment elevation myocardial infarction (STEMI) that has been substantially decreased by primary percutaneous coronary intervention (PCI). This research investigated the impact of duration of ischemia on the severity and improvement of wall motion abnormalities after revascularization and 40-day follow-up. Methods: This study was performed on 60 STEMI patients, treated with 1ry PCI and distributed in two groups; group1: 37 patients presented early before 12h and group II: 23 patients presented late after 12h. Echocardiogram (ECHO) was done for ejection fraction (EF) and resting segmental wall motion abnormalities (RSWMA) detection after revascularization within 24 h of hospitalization and follow up after 40 days. Results: MI complication showed insignificant difference between both groups. Wall motion score index (WMSI) values in group I were significantly decreased relative to group II during the follow-up period (p=0.001). Major improvement in LV ejection fraction from hospital admission to follow-up (p=0.001) in group I from the beginning of chest pain compared to group II. Correlation between time to wire crossing and WMSI showed significant positive correlation after 40 days in group I (p=0.016) with significant negative correlation with EF after 40 days in group I (p=0.018). Conclusions: Ischemic patients with ≤ 12 hours symptoms showed a significant degree of recovery from RWMA on follow up after 40 days.