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Expression of atrial natriuretic factor in the human ventricle is independent of chamber dilation
B S Edwards1, R J Rodeheffer, G S Reeder
1Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, Minnesota 55905.
Insights
Atrial natriuretic factor is commonly found in human heart ventricles, regardless of heart dilation. This finding suggests ventricular atrial natriuretic factor presence is independent of chamber size in heart disease.
Area of Science:
- Cardiology
- Molecular Biology
- Pathophysiology
Background:
- Atrial natriuretic factor (ANF) is primarily known for its role in the atria.
- Ventricular ANF presence and its relationship with heart chamber dilation were not well understood.
- Dilated and restrictive cardiomyopathies present distinct challenges in cardiac function.
Purpose of the Study:
- To investigate the presence of atrial natriuretic factor (ANF) in ventricular tissue.
- To determine if ventricular ANF is dependent on ventricular dilation in heart disease.
- To compare ANF prevalence in dilated versus restrictive cardiomyopathy.
Main Methods:
- Ventricular endomyocardial biopsies were obtained from patients with dilated or restrictive heart disease.
- Immunohistochemical techniques were employed to detect ventricular atrial natriuretic factor.
- Left ventricular end-diastolic volume index and pressure were measured.
Main Results:
- Ventricular atrial natriuretic factor was detected in 15/17 patients with dilated cardiomyopathy.
- Ventricular atrial natriuretic factor was detected in 6/8 patients with restrictive cardiomyopathy.
- Left ventricular end-diastolic volume index was significantly higher in dilated cardiomyopathy.
Conclusions:
- Ventricular atrial natriuretic factor is highly prevalent in patients with systolic or diastolic dysfunction.
- The presence of atrial natriuretic factor in the ventricle appears to be independent of ventricular dilation.
- This suggests a distinct regulatory mechanism for ventricular ANF compared to atrial ANF.
Abstract:
This study investigated the presence of atrial natriuretic factor in ventricular tissue obtained from humans with dilated or restrictive heart disease. In 17 patients with ventricular dilation and impaired systolic function and in 8 patients with restrictive heart disease and preserved systolic function, the presence of ventricular atrial natriuretic factor was investigated in tissue obtained by ventricular endomyocardial biopsy. The objective of the study was to determine if the ventricular presence of atrial natriuretic factor is dependent on ventricular dilation. Left ventricular end-diastolic volume index was greater in the group with dilated cardiomyopathy than in the group with restrictive cardiomyopathy (134 +/- 13 versus 78 +/- 5 ml/m2, p less than 0.05); end-diastolic pressure was elevated in the two groups (20 +/- 2 versus 25 +/- 4 mm Hg, p = NS). With the use of immunohistochemical techniques, ventricular atrial natriuretic factor was clearly detected in 15 of the 17 patients with dilated cardiomyopathy and in 6 of the 8 patients with restrictive cardiomyopathy. This study demonstrates the high prevalence of ventricular atrial natriuretic factor in living patients with either systolic or diastolic dysfunction. Whereas in the atria, stretch or dilation may be an important stimulus, atrial natriuretic factor in the ventricular chamber occurs independent of dilation.