This is a cohort study consisting of 2 patient cohorts. The first cohort will be studied retrospectively, using existing blood samples from different biobanks. Biomarkers will be measured and matched with the etiology of previously diagnosed heart failure by a biomarker panel of heart failure experts. This cohort consists of 100 patients each with (1) ischemic cardiomyopathy, (2) dilated cardiomyopathy and (3) diastolic heart failure. Blood samples will be analyzed for novel biomarkers. Investigators will be seeking biomarker candidate(s) alone or in combination which can predict each category of heart failure etiology with over 85% accuracy and the lowest levels of reclassification. A panel of heart failure experts will be assembled, and the appropriate cut-off values determined. Once this goal has been achieved, the prospective study will go ahead.~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.~Investigators will perform cost-modeling in terms of the potential savings in avoiding unnecessary coronary angiographies or perfusion scans in a typical mixed cohort of heart failure patients based on the marker determined etiology.~A group of healthy volunteers will be added. This group will serve as age matched controls to the prospective cohort of heart failure patients.
The purpose of this study is to evaluate existing biomarkers and see if they can be used to accurately diagnose the etiology of heart failure.