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Atrial natriuretic factor secretion: a role for atrial systolic ejection force?
B Geny1, F Piquard, M Follenius
1Laboratoire d'Explorations Fonctionnelles du Système Circulatoire, Faculté de Médecine Strasbourg, France.
Insights
Elevated atrial natriuretic factor in heart transplant recipients is multifactorial, likely due to hypersecretion rather than reduced clearance. Atrial ejection force did not correlate with this increase.
Area of Science:
- Cardiology
- Nephrology
- Physiology
Background:
- Atrial natriuretic factor (ANF) elevation in heart transplant patients is not fully understood.
- Atrial ejection force (AEF) may influence ANF release, potentially altered by transplantation.
Purpose of the Study:
- To investigate plasma ANF concentrations and maximal AEF in heart transplant recipients versus controls.
- To determine the relationship between ANF levels and AEF in this patient population.
Main Methods:
- Compared 15 heart transplant patients with 8 age- and BMI-matched controls.
- Measured plasma ANF, AEF via echocardiography, and other hemodynamic parameters.
- Analyzed correlations between ANF concentration and AEF.
Main Results:
- Heart transplant patients showed higher serum creatinine, heart rate, mean arterial pressure, and ventricular wall thickness.
- Elevated plasma ANF concentrations were observed in transplant patients (63.9 vs 34.0 pg/mL).
- Despite larger left atrial area in transplant patients, AEF and mitral inflow parameters were similar between groups; no correlation between ANF and AEF was found.
Conclusions:
- Elevated plasma ANF in heart transplant patients is multifactorial, suggesting hypersecretion over decreased clearance.
- Atrial ejection force is unlikely to be a primary driver of the enhanced ANF release in these patients.
Abstract:
The increase in plasma concentration of atrial natriuretic factor in heart transplant patients has not been fully elucidated. Besides an eventual pressure or volume overload leading to passive atrial distension, the atrial tension developed during atrial systole, or atrial ejection force, which may be increased by the transplantation procedure, is an important determinant of atrial natriuretic factor release. We therefore determined the plasma concentration of atrial natriuretic factor and the maximal atrial ejection force in 15 heart transplant patients and 8 controls, matched for age and body mass. Atrial ejection force, as defined as the force exerted by the left atrium to accelerate blood into the left ventricle during atrial systole, was obtained using combined two-dimensional imaging and doppler echocardiography. Serum creatinin concentrations, heart rate [91.9 (SD 13.2) vs 71.8 (SD 10.9) beats.min-1], mean arterial blood pressure [103.9 (SD 9.8) vs 87.4 (SD 5.8) mmHg, 13.85 (SD 1.31) vs 11.65 (SD 0.77) kPa], left ventricular posterior wall thickness and interventricular septum thickness were higher in heart transplant patients compared to controls. Plasma concentration of atrial natriuretic factor was also elevated in heart transplant patients [63.9 (SD 18.1) vs 34.0 (SD 3.2) pg.ml-1; P < 0.001]. In contrast, although the left atrial area was greater in heart transplant patients [28.2 (SD 4.8) vs 15.8 (SD 2.5) cm2; P < 0.001], mitral area, transmitral Doppler A-wave maximal velocity and atrial ejection force were similar in transplant and in control patients [7.7 (SD 3.5) vs 8.9 (SD 2.8) kdyn, 77 (SD 35) vs 89 (SD 28)mN]. No significant correlation was observed between concentration of atrial natriuretic factor and atrial ejection force, either in heart transplant patients or in controls. Thus, the elevated plasma concentration of atrial natriuretic factor observed in these heart transplant patients was multifactorial in origin, and was considered to depend upon an hypersecretion rather than upon a decreased clearance rate. Moreover, it is suggested that the atrial ejection force was unlikely to have participated in this enhanced release of atrial natriuretic factor.