Eleven women with "idiopathic edema" underwent hemodynamic investigation while receiving high and low-sodium diets. During high-sodium diet, cardiac output was normal at rest, and mean pulmonary arterial and capillary wedge blood pressures were moderately elevated. During exercise, there was further elevation of mean pulmonary arterial capillary blood pressures in all patients and increase in stroke volume in all but one patient. During low-sodium diet, resting cardiac output and mean pulmonary arterial and pulmonary capillary blood pressures were lower and the change with exercise was less marked than during high-sodium diet. The one patient who had changes like those of patients with congestive heart failure showed substantial weight loss after digitalization. Evidently heart failure occurs occasionally in patients who seem to have idiopathic edema.
Anis I. Obeid, David H. P. Streeten, Robert H. Eich, Harold Smulyan, Felix E. Schletter, George V. Clift. Cardiac Function in Idiopathic Edema. Arch Intern Med. 1974;134(2):253–258. doi:10.1001/archinte.1974.00320200063007