Cardiac sensitivity to hyperkalemia in adrenalectomized dogs.

In dogs with bilateral adrenalectomy loaded with K by infusion of 2 mEq KCI/kg/hr there is a marked increase of cardiac sensitivity to hyperkalemia. Typical ECG changes begin at lower serum K levels (5-6 mEq/l) and the prelethal arrhythmias that signal the imminent onset of fatal when mean serum K is 7.6 mEq/l, 2.9 mEq/l above the average pre-infusion level. In control dogs, ECG changes start above 8 mEq K/liter, and prelethal arrhythmias appear between 9.5 and 10.2 mEq/l, a mean increase of 5.6 mEq/l above the average preinfusion level.