Background: Right ventricular infarction is a potentially reversible cause of cardiogenic shock so that, accurate diagnosis and therapy have been advocated. Myocardial and annular velocities determined by Doppler tissue imaging (DTI) is a simple technique that has been used to analyze left ventricular function, and opens up also the possibility of assessing right ventricular function. Objective: to assess the right ventricular function by using of tricuspid annular motion and tricuspid annular velocity determined by DTI in patients with AMI. Methods: fifty patients were included in this study, and diagnosed as AMI, 24 of them with inferior infarction ( group І) which subdivided into І(A) (with RV infarction) and І(B) (without RV infarction), while other 26 patients with anterior infarction (group ІІ). Ten healthy volunteers (group ІІІ) were included with matched age and sex. All patients were subjected for full history taking, clinical examination, ECG, echocardiography to determine tricuspid annular plane systolic excursion (TAPSE), LVEF, and RVEF, RV wall motion abnormalities, and presence of tricuspid regurge. DTI was done to detect tricuspid systolic (Sa) and diastolic (Ea, Aa) velocities. Results: there was significant reduction in TAPSE in both group I and group II as compared to group III (p< 0.01, p