An experimental study of cardiac natriuretic peptides as markers of development of congestive heart failure

The use of cardiac peptide measurements as possible diagnostic tools in con gestive heart failure has been extensively discussed in the recent literatu re. Therefore, the aim of this study was to establish a model of experiment al chronic heart failure, and thereby perform a comparative study of secret ion and circulating levels of the cardiac peptides atrial natriuretic pepti de (ANP), N-terminal proatrial natriuretic peptide (N-terminal proANP) and brain natriuretic peptide (BNP) during evolving heart failure. Chronic heart failure was induced in seven pigs by rapid left atrial pacing for three weeks. The effects of failure induction were documented 24 h aft er pacemaker deactivation. Hemodynamic indices of cardiac preload, like pul monary capillary wedge pressure (PCWP) and right atrial pressure (RAP), wer e all considerably increased compared to sham operated controls. Likewise, plasma endothelin-l, noradrenaline, renin activity, aldosterone and angiote nsin II were all markedly increased. Heart failure was accompanied by signi ficant increases in both estimated cardiac secretory rate and plasma concen trations of all three cardiac peptides, significantly correlated to the PCW P. The directional changes during evolving heart failure were similar, alth ough the percentage increase in plasma BNP was much larger than for ANP and N-terminal proANP. In absolute molar terms, however, the BNP concentration changes were minor compared to those of the other two peptides. The larger percentage increase of BNP might indicate its superiority as a marker of h eart failure development, provided a functional assay suitable for clinical use can be designed for a peptide circulating in this low concentration ra nge.