Several studies have demonstrated the usefulness of B-type natriuretic peptide (BNP) dosage in patients referring for acute dyspnea in the emergency department. BNP is strongly associated not only with the evidence but even with the degree of heart failure, and BNP values are particularly increased in the advanced NYHA classes and in patients with poor prognosis. High BNP levels correlate with echocardiographic indexes of left ventricular and right ventricular systolic dysfunction but even better with diastolic dysfunction and degree of left ventricular filling pressure. However, in presence of some clinical confounders, such as obesity, renal insufficiency and anemia, BNP dosage itself cannot be interpretable. Under these circumstances, Doppler echocardiography is able to identify with better accuracy patients affected by heart failure. Algorithms built taking into account clinical and echocardiographic parameters as well as BNP measurements are already available in the guidelines of the European Society of Cardiology on heart failure with normal ejection fraction. They will lead to a better and earlier identification, better risk stratification and management of patients referring for heart failure.