Potassium Depletion and Potassium Supplementation in Cardiac Failure

Relation of plasma aldosterone concentration to diuretic treatment in patients with severe heart disease.

“…The apparent discrepancy with measurements of total body potassium from natural 40K in a whole body counter is probably related to differences in interpretation (Hamer, 1977). The finding of near normal total body potassium in relation to current weight (Davidson et al, 1976;Lawson et al, 1976) is in keeping with the suggestion of Nagant de Deuxchaisnes et al (1961) and Nagent de Deuxchaisnes and Mach (1974) that the loss of potassium seen with total exchangeable potassium measurements is a 'pseudodepletion' caused by loss of lean body mass. The main bulk of body potassium is contained in skeletal muscle.…”

“…Previous studies (White, 1970) have shown that potassium supplements have only a partial effect in correcting the reduced total exchangeable potassium in keeping with the description of hypokalaemia as a simple potassium 'deficiency' by Nagant de Deuxchaisnes et al (1961) and Nagant de Deuxchaisnes and Mach (1974), suggesting that treatment directed to reversing hyperaldosteronism might be a more useful approach to correcting potassium losses in the present situation. Relatively short-term treatment with amiloride has only a minor effect on tissue potassium (Croxson et al, 1972;Davidson and Gillebrand, 1973;Kremer et al, 1977) and attempts to correct potassium depletion caused by loss of lean body mass may be inappropriate, short of haemodynamic correction.…”

“…The reduction in total exchangeable potassium may be, in the main, an indication of a loss of lean body mass as part of wasting which may be occult (Walesby et al, 1978) or evident in the extreme as 'cardiac cachexia', but local critical reductions in intracellular K concentration cannot 316 be excluded (Hamer, 1977). The plasma potassium seems to be part of a labile component of the body potassium which varies without relation to total body stores (Croxson et al, 1972;Nagant de Deuxchaisnes and Mach, 1974;Nicholls et al, 1976) and cannot be used to predict potassium depletion. Plasma potassium may be relatively easily maintained by dietary supplements or aldosterone antagonists with relatively little effect on tissue potassium (White, 1970;Croxson et al, 1972;Davidson and Gillebrand, 1973;Kremer et al, 1977).…”

Potassium Metabolism

“…Such measurements may confuse rather than improve assessment, because of illness-related changes in body composition which produce secondary loss of potassium. The potassium content of adipose tissue is low, so that a disproportionate decrease in muscle mass will give low total potassium without a true deficiency (de Deuxchaisnes and Mach 1974). This measurement is most useful in overall assessment of body composition, or in serial studies of the same subject, but has very limited routine application.…”