This study assessed the relation between B-type natriuretic peptide (BNP) and echocardiographic indexes of left ventricular (LV) filling pressure in 53 patients with stable heart failure and without significant valvular dysfunction. Left atrial volume indexed to body surface area (LAVi), an indicator of chronic LV filling pressure, was correlated with BNP (r = 0.692, p <0.001) and was the strongest independent predictor of elevated levels in this cohort. LAVi was also the best predictor of BNP >or=100 pg/ml, with an area under the receiver-operating characteristic curve of 0.85 (95% confidence interval 0.74 to 0.96, p <0.001). Using the optimal cutoff of >31 ml/m(2), LAVi had a sensitivity of 92% and a specificity of 65% for BNP >or=100 pg/ml. Patients with LAVi >31 ml/m(2) had a median BNP of 122 pg/ml, compared with 21 pg/ml in patients with LAVi <or=31 ml/m(2) (p <0.001). These findings suggest that in patients with stable heart failure, BNP levels are related to chronic LV filling pressures. This may help explain the relatively modest correlation between BNP and acute measures of LV filling and the heterogeneity in BNP levels in patients with stable heart failure.