Salivary electrolytes and digitalis.

The hypothesis that an increase in salivary concentration of certain electrolytes (Ca X K) is a sign of digitalis intoxication was tested in 16 untreated health volunteers, 29 digitalized heart failure patients and four further healthy volunteers given digoxin. Salivary electrolyte levels were raised in only about half the digitalized patients and blood levels of digoxin were not always higher in these patients than in those with normal electrolyte concentrations. The salivary electrolyte levels of the healthy volunteers given digoxin remained normal. These findings would seem to rule out the possibility that digitalis is responsible for the changes in salivary electrolytes observed in certain cases of heart failure. A very marked correlation (P less than 0.00002 by Fisher's exact probability test) was found, however, between an increase in the product of salivary calcium and potassium (Casal X Ksal) and the presence of clinical signs of poorly compensated heart failure. It is suggested that this might be a result of adrenergic stimulation, which is known to occur in heart failure, affecting the salivary glands.