Objectives: To investigate the relationships between N-terminal atrial natriuretic peptide (N-ANP) and left ventricular geometry and function.
Design: A cross-sectional study of a population-based cohort.
Setting: Follow-up of a health survey in Uppsala county, Sweden.
Subjects: Two hundred and five men aged 70.
Main outcome measures: A Delfia sandwich immunoassay was used to measure the plasma levels of N-ANP. M-mode and Doppler echocardiographic examinations were used to measure left ventricular dimensions, mass, geometry and systolic function and to classify the subjects into four groups (normal geometry, concentric remodelling, concentric hypertrophy or eccentric hypertrophy). Left ventricular systolic dysfunction was defined as a left ventricular ejection fraction </= 0.40.
Results: Plasma levels of N-ANP were significantly increased in subjects with left ventricular dysfunction compared to healthy subjects (702 +/- 486, n = 14 vs. 277 +/- 201 pmol L-1, n = 118, P < 0.0001), but there was a great overlap between the groups. N-ANP differed significantly between the four different left ventricular geometric groups (P = 0.02) with the highest N-ANP levels in the subjects with left ventricular eccentric hypertrophy (n = 40). However, N-ANP levels were no longer significantly associated with left ventricular geometry when taking the ejection fraction into account.
Conclusions: This study showed that N-ANP levels were significantly elevated in subjects with left ventricular dysfunction, as well as in subjects with left ventricular hypertrophy. However, the increase in N-ANP seen in the eccentric hypertrophy group was mainly due to a decreased ejection fraction.