Introduction: Heart failure (HF) is a chronic syndrome that influences survival & quality of life. over the past 20 years, hospitalizations for heart failure have almost tripled, making heart failure the most common cause of hospitalization. Objective: evaluation of relationship between functional capacity by duke activity status index(DASI) in chronic heart failure patients and the right atrial volume index. Materials and methods: study was conducted on 40 patients who were admitted in the hospital with heart failure.All patients were subjected to detailed history, physical examination, electrocardiography, laboratory investigations, 2D echocardiography & tissue Doppler imaging and assessment of functional capacity using DASI. Results: Out of 40 patients, 10 (25%) had DASI<10 and 30 (75%) patients had DASI>10, according to functional capacity between the two groups, group I Vo2 peak (ml/min) mean is 12.98±1.45 and DASI score ranged from (4.5-9.95) with a median 8.6, in group II Vo2 peak (ml/min) mean is 21.89±4 and DASI score ranged from (23.3- 36.7) with a median 28.7with p value <0.001. RAVI had a significant correlation between the two groups with p-value <0.001. Also, DASI have a strong correlation with RAVI (r=1.139 & p=0.029). Conclusions: RAVI predicts functional capacity in chronic stable heart failure patients. 
