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Relationship of atrial natriuretic factor to left ventricular volume and mass
M J Roman1, R B Devereux, S A Atlas
1Department of Medicine, New York Hospital-Cornell Medical Center, NY 10021.
Insights
Left atrial size, not left ventricular changes, is the primary driver of elevated atrial natriuretic factor levels in heart conditions. This finding highlights the importance of left atrial dimension in regulating this crucial hormone.
Area of Science:
- Cardiology
- Endocrinology
- Physiology
Background:
- Atrial natriuretic factor (ANF) is mainly produced by the atria, but also by the hypertrophied left ventricle.
- Understanding factors influencing ANF levels is crucial for cardiovascular health.
Purpose of the Study:
- To investigate the distinct impacts of left atrial and left ventricular dilatation and hypertrophy on human ANF levels.
- To determine the primary determinant of elevated ANF in cardiac conditions.
Main Methods:
- Compared left atrial and ventricular dimensions and mass in 49 normal subjects, 33 with aortic regurgitation, and 15 with mitral regurgitation.
- Measured plasma ANF levels.
- Utilized correlation and multivariate analysis.
Main Results:
- Patients with mitral regurgitation showed enlarged left atria and elevated ANF. Patients with aortic regurgitation had enlarged left ventricles but normal ANF.
- ANF levels strongly correlated with left atrial dimension and volume (r=0.62-0.64).
- Left atrial volume was a stronger independent predictor of ANF than age or left ventricular variables.
Conclusions:
- Left atrial size is a more significant determinant of plasma ANF levels than left ventricular hypertrophy or dilatation.
- These findings emphasize the critical role of the left atrium in ANF regulation, particularly in conditions like mitral regurgitation.
Abstract:
Although atrial natriuretic factor is primarily of atrial origin, recent observations indicate that the hormone is also synthesized by hypertrophied left ventricular myocardium. To assess the separate influences of left ventricular and left atrial dilatation and left ventricular hypertrophy on human atrial natriuretic factor levels, left atrial dimension and volume and left ventricular dimension and mass were compared in 49 normal subjects, in 33 patients with chronic aortic regurgitation, and in 15 patients with chronic mitral regurgitation. When compared with normal subjects, patients with chronic aortic and mitral regurgitation had similarly dilated and hypertrophied left ventricles (p less than 0.0005), while only mitral regurgitation patients had significantly enlarged (p less than 0.0005) mean left atrial dimension and volume. Likewise, plasma atrial natriuretic factor was elevated among patients with mitral regurgitation (60.3 +/- 47.0 fmol/ml) but was normal in patients with aortic regurgitation (19.0 +/- 11.0 fmol/ml versus 12.4 +/- 5.2 fmol/ml in normals; both p less than 0.0005 versus mitral regurgitation). Among all 97 subjects, atrial natriuretic factor levels correlated more closely with left atrial dimension and volume (r = 0.62 and 0.64, p less than 0.0005) than with left ventricular dimension (r = 0.44, p less than 0.0005) or mass (r = 0.40, p less than 0.0005). In addition, multivariate analysis indicated that left atrial volume bore a stronger independent relationship to plasma atrial natriuretic factor levels than either age or left ventricular variables.(ABSTRACT TRUNCATED AT 250 WORDS)