The objective of this study was to critically evaluate the usefulness of atrial natriuretic factor (ANF), the N-terminal fragment of the ANF pro-hormone (pro-ANF) and B-type (brain) natriuretic peptide (BNP) determination as screening tests for identifying patients with mild left ventricular (LV) impairment. The sample consisted of a consecutive series of 254 patients undergoing diagnostic left-sided cardiac catheterization. Logistic regression analysis showed that plasma BNP was the best predictor of increased LV end-diastolic pressure, decreased LV ejection fraction and LV dysfunction (LV ejection fraction < or = 45% and LV end-diastolic pressure > or = 15 mm Hg). For the detection of LV dysfunction the areas under the receiver-operating characteristic function, an index of overall diagnostic accuracy, were 0.789 for BNP, 0.665 for ANF and 0.610 for pro-ANF. In conclusion, plasma BNP appears to be a better indicator of LV function than plasma ANF or pro-ANF. However, the overall diagnostic value of circulating ANF, pro-ANF, and BNP as indicators of mild LV dysfunction is relatively modest.