INTRODUCTION: The aim of the present study was to examine the value of the right atrial volume index (RAVI) as predictor of functional capacity in patients with heart failure.METHODS: A total of 51 patients with stable chronic heart failure of ischaemic or non-ischaemic aetiology were prospectively enrolled. The systolic function of the right ventricle was quantified using the tricuspid annular plane systolic excursion (TAPSE). Right atrial volume was measured in the apical 4-chamber view and was indexed to body surface area. The functional capacity was assessed by the Duke Activity Status Index (DASI).RESULTS: Patients with a low functional capacity (DASI<10) had lower TAPSE (1.4 ± 0.3 cm versus 2.0 ± 0.4 cm, p<0.001), higher RAVI (42 ± 15 ml/m(2) versus 22 ± 9 ml/m(2), p<0.001), higher estimated right ventricular systolic pressure (61 ± 13 mmHg versus 40 ± 16 mmHg, p<0.001), larger right ventricular end-diastolic diameter (4.7 ± 0.8 cm versus 3.6 ± 0.7 cm, p<0.001) and lower left ventricular ejection fraction (26 ± 6% versus 30 ± 7%, p=0.022). Multivariate analysis revealed that TAPSE was the single independent predictor of DASI. In the subgroup of patients with reduced right ventricular systolic function (TAPSE<2 cm), RAVI was the single independent predictor of low DASI. In the overall population RAVI=30.6 ml/m(2) had 75% sensitivity and 83% specificity in predicting DASI<10. Within the subgroup of patients with TAPSE<2 cm, RAVI=30.6 ml/m(2) had better sensitivity and specificity (79% and 90% respectively) in predicting DASI<10.CONCLUSIONS: Increased right atrial volume index predicts low functional capacity quantified by the Duke Activity Status Index in patients with stable chronic heart failure.