BACKGROUND: Regional sampling may identify sites of production or removal of novel biomarkers in the circulation; their relationship to haemodynamic measurements may clarify their association with the pathophysiology of heart failure. METHODS: Samples were obtained from up to eight circulatory sites from 22 patients with left ventricular dysfunction undergoing elective cardiac catheterisation. The plasma concentrations (PC) of six biomarkers [mid-regional pro-atrial natriuretic peptide (MR-proANP), C-terminal pro-endothelin-1 (CT-proET-1), mid-regional pro-adreno-medullin (MR-proADM), high sensitivity pro-calcitonin (hsPCT), copeptin and galectin-3 (Gal-3)] were measured. RESULTS: Plasma concentrations of MR-proANP were highest in the pulmonary artery (PA) and left ventricle, suggesting myocardial production. Lower concentrations of copeptin, CT-proET-1, MR-proADM and hsPCT were found in the supra-renal inferior vena cava (SRIVC) sample suggesting renal extraction. Plasma concentrations of Galectin-3 varied little by sampling site. Plasma concentrations of MR-proANP (R=0.69, P=0.002), MR-proADM (R=0.51, P=0.03), CT-proET-1 (R=0.60, P=0.009) and Copeptin (R=0.47, P<0.05) measured from PA samples correlated with PA systolic pressure. There was no relation between any measured marker and cardiac index. CONCLUSIONS: Regional sampling shows variation in the plasma concentration of various novel peptides that provides clues to sites of net production and removal. Plasma concentrations of several biomarkers were positively correlated with pulmonary artery pressure.