ATRIAL NATRIURETIC PEPTIDE (ANP): THE RELATIONSHIP WITH VOLUME, TACHYCARDIA AND CRITICAL ILLNESS

Abstract

This study examines the effect of volume overload, atrial heart rate and critical illness on ANP levels in children. ANP levels were measured in 7 children undergoing dialysis(D), 4 children undergoing cardiac catheterization with electrophysiological pacing(EP), and 4 children in the ICU with pulmonary artery (PA) catheters. Thirty-four children were controls. The ANa results (RIA technique) are expressed in pg/ml (mean±SD). ANF levels in all 3 study groups were significantly different from normal (6.5±4.9) as follows: pre D pts, 139.7 ± 71.3 (p <.001); EP, 48.5^20.5 (p<.02); ICU patients, 104.0 ± 44.9 (p<.001). Pre and post D samples were significantly different (139.7±71.3 vs. 90.7±50.6, p<.004)and the change in ANF was correlated with the percent weight loss (R = .733). Pacing increased heart rates (117 ± 17 vs. 157 ± 20, p <.01) and ANP levels correlated with the increase in heart rate (48.5 ± 20.5 vs. 203.0 ± 66.0., p <.005, R = .66). ICU patients had elevated but statistically equivalent ANP levels in central venous, PA and arterial samples. CONCLUSION: ANP levels are increased in children with fluid overload, elevated heart rates and in critical illness. Removal of fluid from volume overloaded patients directly correlated with a decrease in ANP. Pacing of the right atrium in children caused a significant elevation of ANP confirming the association of tachycardia with ANP.