Introduction: lesions in the proximal segment of the LAD coronary artery present a high-risk lesion, as this important anatomical location of atherosclerotic plaques is associated with increased mortality. Patients with chronic ischemic LV dysfunction but viable myocardium will have better LV geometry after revascularization, which in turn will enhance long-term outcome.  Objective: to assess the impact of PCI on critical proximal lesion of LAD artery on LV functions by echocardiography and tissue doppler study. Materials and methods: We included 50 patients older than 18 years old with critical proximal LAD lesion who were undergoing elective PCI in cardiology unit, faculty of medicine, Al-Azhar University, Assiut from April 2021 to November 2021. Results: For E/A ratio, we found that the reduction in this ratio was significantly higher among those with preserved EF compared to others. The increase in IVRT and DT over 1 month period was statistically higher among those with preserved EF when compared with others. For E/A ratio, we found that the reduction in this ratio was significantly higher among those with preserved EF compared to others. Also, we found that average E/′E ratio was significantly reduced among those with preserved EF when compared to others.