Primary Outcome Measures:
- Plasma BNP levels at T0 to test the optimal values of measuring plasma BNP for diagnosis of HF in patients older than 80 years. [ Time Frame: 6 months ]
Secondary Outcome Measures:
- Plasma BNP levels at 3 times (T0, T48, Tend) to test the usefulness of measuring plasma BNP : 1.at T0 : in diagnosing HF using a 2-threshold up-and down-approach [ Time Frame: 6 months ]
- 2.at T48 : in diagnosing and prognosing HF using a 2nd assay after 48 hours of treatment [ Time Frame: 6 months ]
- 3.at Tend : in prognosing HF using a 3rd assay after the acute phase (composite criteria) [ Time Frame: 6 months ]
Measurement of BNP concentration is approved for use in the diagnosis of heart failure (HF) in elderly patients below 80 years of age. The value of plasma BNP assays as diagnostic tools has not been determined in very elderly populations because the plasma BNP increases with age. This large, multicenter, prospective, observational, study in 300 participants is aimed to prospectively test the usefulness of measuring plasma BNP for diagnosis of HF in dyspneic patients aged 80 and older.