Plasma Atrial Natriuretic Factor in Obesity: Correlation to Echocardiography.

The plasma levels of atrial natriuretic factor (ANF), renin activity and aldosterone level in a lean control group (group I, n=20), obese normotensive individuals (group II, n=46), and obese hypertensives (group III, n=14) were estimated along with echocardiographic examination. According to findings obtained from echocardiography, normotensive and hypertensive obese subjects with impaired left ventricular diastolic function were subclassified as groups IIa and IIIa, respectively. ANF was found to be increased in obese normotensive and obese hypertensive groups compared with the control group level. Obese normotensive and obese hypertensive subjects with impaired left ventricular function were found to have higher plasma ANF than their unimpaired counterparts. An inverse relation was found between plasma ANF and plasma renin activity or aldosterone level. There were a significant decrease in fractional shortening and increase in left atrial diameter in groups IIa and IIIa compared with control group. We conclude that impairment of the left ventricular diastolic function caused by hypertrophy of the left ventricle in obese normotensives and obese hypertensives produces elevation of pressure in the left atrium and an increase in the secretion of ANF. Cardiac chamber in pressure is a reflection of this increased circulating ANF.