Background: Assessment of function of the right side of the heart in cases of left ventricular dysfunction has been widely studied but the sensitive and specific echocardiographic parameter to be tested is still a matter of controversy. Right ventricular function is related to left ventricular function by ventricular independence so function of both should be assessed carefully. The objective of this study was to evaluate the effects of left ventricular systolic dysfunction on right ventricular systolic and diastolic functions and pulmonary pressure using conventional and tissue Doppler echocardiography. Patients and Methods: Sixty patients (39 males and 21 females) with heart failure due to left ventricular systolic dysfunction diagnosed by echocardiography presented to the Baghdad Teaching Hospital and the Iraqi Centre of Heart Diseases were included in this study. The mean age of study patients was 57±11years. Ethical approval was obtained from the ethical committee of college of Medicine/ University of Baghdad. Informed consent was obtained from all patients included in the study. Sinus rhythm and mild to severe left ventricular systolic dysfunction were the inclusion criteria. All patients underwent a standard 2-dimensional and tissue Doppler echocardiography. Results: Of the study patients, 63.3% had abnormal right ventricle myocardial performance index. 35% of the sample have abnormal tricuspid annular plane systolic excursion. Pulmonary artery systolic pressure was elevated in 28.3% of patients. The right ventricular performance index was the most sensitive parameter of right ventricular dysfunction with a sensitivity 100% but the specificity was about 52%, while tricuspid annular plane systolic excursion was less sensitive and more specific than right ventricle myocardial performance index with a sensitivity of 38% and specificity of 84%. Conclusion: The right ventricular function is affected in patients with left ventricular dysfunction. To study right ventricular function; right ventricular myocardial performance index which measure both systolic and diastolic functions is more sensitive than TAPSE which
