Exchangeable potassium content of the body in congestive failure; changes during treatment.

The increase in body weight in congestive heart failure is generally attributed to the retention of sodium and water in the extracellular compartment. Important changes also occur in the intra-cellular space, particularly in the metabolism of potassium. The isotope-dilution technic permits more precise determination of the exchangeable potassium content of the body in congestive failure before and during diuresis. The results of 27 such determinations in 11 patients with congestive heart failure are correlated with the clinical status of the patient and the serum concentration. IT HAS generally been assumed that an increase in body weight that occurs during congestive heart failure is due to retention of sodium and water in the extracellular compartment. Recent studies, however, have suggested that changes also occur in the intracellu-lar phase, and in the metabolism of potassium as well as sodium.'-3 The external balance method, which has been used in most previous studies of this problem, does not permit the direct measurement in vivo of the body's potassium content. This difficulty can be overcome by the use of the isotope-dilution technic-a technic that has previously been applied to studies on the pathophysiology of other disease states.4 The purpose of the present study was to determine , by use of the in vivo isotope-dilution technic, changes in the exchangeable potassium content of the body during the therapy of con-gestive failure. Serial determinations of the ex-changeable potassium content were made in hospitalized patients, and the changes in this value were correlated with the alterations in serum electrolytes, body weight, and the clinical response. MATERIAL AND METHODS Subjects. Eleven patients with advanced conges-tive failure, 8 men and 3 women, were studied. Their ages ranged from 48 to 83 years. In 4 subjects, the cause of the congestion was rheumatic heart disease; in 4 subjects, arteriosclerotic heart disease; in 2 subjects , pulmonary fibrosis and emphysema with cor pulmonale; and in 1 subject, syphilitic heart disease. Most of these individuals had previously been followed in the Outpatient Clinic and had received maintenance doses of digitalis, ammonium chloride, and aminophylline, and periodic injections of a mercurial diuretic. Only 1 patient (case 5) had not previously been treated with digitalis. When admitted to the hospital, all had gross edema. The general plan was to make at least 2 deter-minations of the exchangeable potassium content, the serum concentrations of sodium and potassium, and the body weight during hospitalization. In some instances, …