Distribution of body sodium, potassium, and water and the excretion of aldosterone in dogs with spontaneous heart failure

Abstract

A series of studies was made in the compensated and decompensated phases of spontaneously occurring canine congestive heart failure secondary to mitral insufficiency of undetermined etiology. In 12 dogs, results were obtained for body composition and distribution of water, sodium, and potassium, and for the excretion of aldosterone. The data show highly significant increases in plasma volume, red-cell mass, extracellular water and extracellular sodium content, and in the excretion of aldosterone. Extracellular concentration of sodium and potassium remains normal, although serum potassium is increased slightly (p = 0.05) over that of the compensated state. Intracellular water is increased 11 per cent, and intracellular potassium concentration is decreased 6 per cent. Although neither change reaches statistical significance, the latter is suggestively close (p = 0.08). Intracellular sodium concentration varies considerably, but, on the average, is negligibly increased. The results in the compensated animals approximate the results in normal man and dog. The pattern of response found in decompensation is virtually identical to the usual response to low-output right heart failure in man.