Different secretion profiles of atrial and brain natriuretic peptides after acute volume loading in patients with ischemic heart disease.

In order to clarify the different secretion profiles of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in response to acute hemodynamic change by volume expansion, we measured plasma ANP and BNP levels after intravenous isotonic saline infusion for 3 min at a rate of 3 ml/kg body weight/min in 15 patients with ischemic heart disease. Plasma ANP and BNP levels before the volume loading were 30.7 +/- 16.7 and 19.4 +/- 24.6 pg/ml, respectively. Five and 10 minutes after infusion, plasma ANP levels rose significantly to 43.5 +/- 20.7 and to 46.0 +/- 22.5 pg/ml, respectively (p < 0.01), and plasma BNP levels rose significantly to 27.3 +/- 30.8 and 24.8 +/- 23.2 pg/ ml, respectively (p < 0.01). The BNP/ANP ratio was not affected by volume loading. The maximum increments of plasma ANP level correlated significantly with those of the mean pulmonary capillary wedge pressure (mPCWP, r = 0.78, p < 0.01) or left ventricular end-diastolic pressure (LVEDP, r = 0.86, p < 0.01). However, there were no significant correlations between the maximum increments of plasma BNP levels and those of mPCWP or LVEDP. Plasma ANP level can be a useful parameter for atrial pressure even if the hemodynamic state change rapidly. However, in an early phase of ventricular overload BNP secretion is not increased sufficiently despite the raised LVEDP, and plasma BNP level may not always reflect ventricular hemodynamics.