Atrial natriuretic peptide: relation to left ventricular filling properties in patients with systemic sclerosis

To determine the relation between left ventricular filling properties and plasma atrial natriuretic peptide in systemic sclerosis, we evaluated 30 consecutive patients and 48 age- and sex-matched controls. The venous plasma atrial natriuretic peptide was measured by radio-immunoassay. Left ventricular involvement was evaluated by echocardiography and mitral regurgitation was evaluated by Doppler. The patient group had markedly elevated plasma atrial natriuretic peptide as compared to the matched controls, (239.4 +/- 59 vs. 178.2 +/- 36 pmol/l, P < 0.0005). We found signs of impaired left ventricular filling properties among the patients with an increase of the Doppler A-wave velocity and A/E ratio. A relative reduction of early filling was found in spite of some degree of mitral regurgitation in two-thirds of the patients. The plasma atrial natriuretic peptide concentration was related to the A-wave velocity (r = 0.44, P < 0.0005), the A/E ratio (r = 0.40, P < 0.005), and also to the degree of mitral regurgitation (r = 0.43, P < 0.005). The relationship to the A-wave velocity remained when considering possible confounding factors. We conclude that the previously observed fibrotic process in systemic sclerosis does not prevent production and liberation of plasma atrial natriuretic peptide in relation to factors distending the left atrium, such as altered left ventricular filling properties and the presence of mitral regurgitation. However, the moderate relationships between atrial natriuretic peptide and haemodynamic variables indicate that the peptide might also be an independent indicator of cardiac involvement in systemic sclerosis.