FUNCTIONAL EXPLANATION FOR INCREASED ATRIAL-NATRIURETIC-PEPTIDE IN SYSTEMIC-SCLEROSIS

We related atrial natriuretic peptide (ANP) among 30 consecutive patie nts with systemic sclerosis (SScl) and 48 gender- and age-matched cont rols to the measurements of left ventricular CW) function as evaluated by echocardiography and external pulse curves to determine possible c ausative factors for an increased Ir:vel of plasma ANP. The patients h ad a markedly elevated plasma ANP level (239.4 +/- 59 vs. 178.2 +/- 36 pmol/l, p < 0.0005), which was not related to LV systolic function, h eart rate, or blood pressure. Patients had LV hypertrophy and plasma A NP correlated directly to interventricular septal thickness (r = 0.41, p < 0.005), LV posterior wall thickness (r = 0.32, p < 0.01), and wal l thickness to cavity dimension (r= 0.44, p < 0.0005), LV mass index ( r = 0.40, p < 0.005). LV early filling properties were impaired, with reduction of atrial emptying index (p < 0.0005) and increased contribu tion of atrial contraction to LV filling. Plasma ANP correlated to atr ial emptying index (r = 0.41, p < 0.0005) and to apex-cardiographic a wave (r =: 0.28, p < 0.05). Plasma ANP was also related to left atrial dimension index (r = 0.27, p < 0.05), and was still related to atrial emptying index, but not to left atrial dimension, when considering th e degree of LV hypertrophy in multivariate analysis. We conclude that ANP is elevated in patients with SScl. Reduced LV compliance, probably due to increased fibrosis, may cause changes in atrial pressure suffi cient to stimulate ANP production without systolic dysfunction as a pr erequisite.