In the second cohort, biomarkers will be measured and used to diagnose the etiology of heart failure for each subject. This diagnosis will then be compared to the diagnosis from results of the usual diagnostic tests. Investigators will recruit 450 patients admitted to hospital or outpatient clinics with recently diagnosed heart failure (<2 years) and test for different biomarkers. Using the biomarker values, investigators will predict their heart failure etiology in an objective manner. The patients will then undergo definitive etiological workup as usual to establish the actual etiology of the heart failure. The duration of a typical etiological workup is about 3 days for hospitalized patients and up to 8 weeks for patients admitted to outpatient clinics. The predictive accuracy of the new heart failure panel will be compared to clinical assessment.