In recent years new tests to diagnose heart failure have become available. We are evaluating a new test called B-type natriuretic peptide(BNP)in patients presenting to the Emergency Department with shortness of breath. Patients are randomised into whether they will receive the new test or not. In the patient group where the test is positive, standardised approach that will optimise heart failure treatment will be introduced. We hypothesise that with this approach we will improve the clinical care of patients who present to the Emergency Department with shortness of breath. Measures of outcomes will be the accuracy of diagnosis 2 hours after presentation, 30 day mortality, hospital and ICU admission rates and quality of life at 30days.