Natriuretic peptides in patients with diastolic dysfunction due to idiopathic dilated cardiomyopathy

Aims The degree of systolic dysfunction does not always correlate with func tional impairment in patients with congestive heart failure. In contrast, d iastolic dysfunction correlates well with functional impairment. In heart f ailure, both elevation of N-terminal proatrial natriuretic peptide and B-ty pe natriuretic peptide are markers of a poor prognosis. Methods We investigated 32 patients (26 male, 6 female; mean age 55 +/- 2 y ears) with dilated cardiomyopathy and sinus rhythm. M-mode echocardiography and 2D-echocardiography were carried out in each patient. Pulsed-wave Dopp ler inflow signals were obtained and the following parameters were measured : maximal E wave and maximal A wave velocity, E/A ratio, E wave deceleratio n time, A wave deceleration time. Immediately after echocardiography blood samples were collected from patients in the supine position. N-terminal pro ANP and brain natriuretic peptide were measured using a radioimmuno assay. Results The left ventricular ejection fraction was 34 +/- 1%, the left vent ricular end-diastolic diameter on M-mode echocardiography was 68 +/- 1 mm, while left atrial diameter was 45 +/- 1 mm. Univariate analysis revealed a significant correlation between both left atrial diameter and ejection frac tion and N-terminal proANP and brain natriuretic peptide. All transmitral D oppler parameters showed a significant correlation with N-terminal proANP a nd brain natriuretic peptide. On forward stepwise regression analysis, left atrial diameter and ejection fraction were able to predict both N-terminal proANP and brain natriuretic peptide. However, of the diastolic parameters only the EIA ratio remained significant. Mildly symptomatic patients diffe red significantly from severely symptomatic patients in all Doppler paramet ers. Mildly symptomatic patients had significantly lower levels of N-termin al proANP (0.571 +/- 0.079 vs 2.282 +/- 0.340 nmol.1(-1); P < 0.001) and br ain natriuretic peptide (51 +/- 14.8 vs 474.2 +/- 86.8 pg.ml(-1); P < 0.001 ). Conclusion There is a close relationship between natriuretic peptides and d iastolic Doppler parameters of left ventricular filling in patients with di lated cardiomyopathy. There is also a significant difference between patien ts with mild and severe functional impairment regarding both natriuretic pe ptides and transmitral Doppler parameters.