To evaluate the possible role of atrial natriuretic peptides ANF (1-98) and ANF (99-126) as diagnostic parameters of atrial distension, measurements of peptide levels were performed in 47 patients with chronic ischemic and/or left sided valvular heart disease. Plasma samples were drawn from the pulmonary artery (PA) and superior vena cava (SVC) during diagnostic right heart catheterization. Forty of the patients also underwent left heart haemodynamic measurements, and in 28 patients two dimensional echocardiography with determination of left atrial diameter was performed. Enhanced plasma concentrations of both peptides were observed with increasing severity of heart failure assessed by the NYHA classification. Mean plasma levels of both peptides were closely correlated to mean pulmonary artery pressure (ANF (1-98): n = 47, r = 0.69 (SVC)/r = 0.72 (PA), p < 0.0001; ANF (99-126): n = 46, r = 0.75 (SVC)/r = 0.68 (PA), p < 0.0001) and mean pulmonary capillary wedge pressure (ANF (1-98): n = 47, r = 0.69 (SVC)/r = 0.72 (PA), p < 0.0001; ANF (99-126): n = 46, r = 0.70 (SVC)/r = 0.64 (PA), p < 0.0001). Positive correlations were also obtained between peptide levels and mean right atrial pressure and left ventricular end-diastolic pressure. When patients with high right atrial pressures (n = 2) were excluded from analysis, a significant correlation was found between peptide levels and echocardiography assessed left atrial diameter. The present study demonstrates the close correlation between concentrations of both atrial peptides and cardiopulmonary haemodynamics in patients with chronic heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)