Plasma B-type natriuretic peptide as a marker of myocardial asynchrony.

Objectives: Myocardial asynchrony in postinfarction patients with intraventricular conduction defects (IVCD) may influence plasma levels of B-type natriuretic peptide (BNP). The aim of the study is to evaluate asynchrony parameters in postinfarction patients with IVCD and to define the relationship between plasma levels of BNP and echocardiographic parameters of asynchrony.

Methods: The study included 158 patients 6 months after myocardial infarction (MI): 126 patients with IVCD and 32 patients without IVCD. Plasma levels of BNP were measured using an immunoenzymatic method. Left ventricular (LV) function was evaluated in echocardiography.

Results: In patients with post-MI IVCD, the mean plasma level of BNP was 280.2 +/- 340.2 versus 181.7 +/- 270.4 pg/ml (p < 0.001) and they had significantly higher parameters of interventricular asynchrony as compared with subjects without postinfarction IVCD. Multifactorial regression analysis showed that in patients with an ejection fraction (EF) > or =50%, interventricular asynchrony and intraventricular delay significantly influenced the BNP level. In patients with an EF <50%, BNP levels were correlated with the magnitude of the EF.

Conclusion: Plasma levels of BNP 6 months after MI depend not only on parameters of LV function but also on LV asynchrony and may serve as its marker in patients with IVCD and preserved LV systolic function.