Elevated filling pressures are associated with heart failure deterioration, but mechanisms underlying this association remain poorly understood. We sought to investigate whether or not elevated filling pressures are associated with increased collagen turnover, evaluated by procollagen type III aminoterminal peptide (PIIINP) levels, in stable systolic heart failure. Eighty patients with heart failure with severe systolic dysfunction (ejection fraction 26 +/- 7%) were included. Patients underwent simultaneous echocardiogram with evaluation of haemodynamic parameters and blood sampling for PIIINP measurement. Mean PIIINP level was 6.11 +/- 2.62 microg l(-1). PIIINP was positively associated with estimated right atrial pressure (RAP) (r = 0.36; p = 0.001). Mean PIIINP values were 5.04 +/- 2.42 microg l(-1) in patients with estimated RAP < or = 5 mmHg, and 7.59 +/- 2.54 microg l(-1) in those with RAP > 15 mmHg (p < 0.01). In conclusion, elevated right-side filling pressures are associated with evidence of active extracellular matrix turnover, as indicated by elevated PIIINP levels, in stable systolic heart failure. Activation of extracellular matrix turnover may be implicated in the accelerated progression of heart failure syndromes seen in patients with persistent congestion.