Atrial natriuretic factor in the pleural fluid of congestive heart failure patients

To investigate the possibility that atrial natriuretic factor might be secreted into the pleural fluid of patients with congestive heart failure who are known to have high concentrations of this new peptide hormone circulating in their plasma, six patients with class 2 New York Heart Association classified congestive heart failure had simultaneos measurement of plasma and pleural fluid atrial natriuretic factor concentrations. Atrial natriuretic factor was found in high concentrations in the pleural fluid of all of these patients. The concentration of atrial natriuretic factor in pleural fluid was nearly equal to the concentration in plasma of these patients. Their plasma levels were double the plasma concentration of this peptide hormone in 54 persons without congestive heart failure. These preliminary findings demonstrate that atrial natriuretic factor is present in pleural fluid of patients with congestive heart failure, but whether or not this secretion of atrial natriuretic factor into the pleural fluid helps the lung clear the fluid present in the lung in congestive heart failure cannot be determined from the present investigation.