Background: It has been well established that early restoration of patency of an infractrelated artery by percutaneous coronary intervention (PCI) in patients (pts) with recentmyocardial infarction(MI) may preserve left ventricular (LV) global function and also preventleft ventricle remodeling. There were controversies however concerning the possible benefitsof delayed (within 30 days) restoration of patency of an infarct-related artery of patients.Aim: To evaluate left ventricular remodeling & function after acute MI, comparing primaryversus delayed PCI.Methods: Forty patients (35 males, 5 females mean age 50.9) were included in the study withrecent MI, and were divided into 2 groups. Group A (20 pts) who had the chance ofundergoing primary PCI within a mean 5.4 hrs from the onset of chest pain with a door toballoon time 1.6 hrs and group B (20 pts) with delayed hospitization (i.e > 12 hours) whoneither received thrombolytic nor did primary PCI ,but were scheduled for routine PCI within a mean of 20.7 days. The LV function and dimensions were assessed by serialechocardiographic readings measuring left ventricle end diastolic volume (LVEDV), leftventricle end systolic volume (LVESV), ejection fraction (EF), regional wall motion scoringindex (RWMI) at 24 hrs of admission and after 3 and six months. Results were expressed asmean value ± SD, with a p value less than 0.05 considered significantResults: At three months compared to delayed PCI group ,group A showed significantimprovement in RWMI (from 1.9 ± 0.3 to 1.27 ± 0.13) vs (1.6± 0.2 to 1.38± 0.18) in groupB respectively (P value 0.032). There was a non significant increase in LVEDV values inthe two groups, (from 101 ±17.6 to 109± 20.1 in group A vs 98.3± 22.3 to 106.3± 22.1 inthe delayed group). The change in EF value was nearly the same in both groups; (59.6%±3.9 at base line to 58..5%± .5 in group A vs 57.1%±9.3 to55.2%± 6.4 in group B).At six months, there was no more improvement in the RWMI in both groups but thedelayed group showed marked increase in LVEDV ( from 98.3±22.3 at base line to 138±32.96, i.e 28.9% increase in volume) versus <20 % changes in the primary group (from 101±17.6 at base line to 115± 32.14, P= <0.05). Whereas the EF % value was nearly preserved ingroup A (59.6 % ± 3.9 at base line to 59.9% ± 6.81), there was remarkable deterioration in theEF % in the delayed group (from 57.1±9.3 at base line to 51.8± 10.8) after six monthConclusions: Despite the enthusiasm to open artery hypothesis, i.e restoring patencyirrespective of time, our data showed that early and immediate revascularization (primaryPCI) is superior to delayed intervention. Therefore prompt restoration of patency is highlyrecommended for myocardial salvage and for preserving left ventricular function andprevention of LV remodeling.