Hypokalemia in cardiac decompensation.

The problem of hypokalemia in cardiac decompensation is reviewed. Some methodological sources of error in connection with blood sampling is discussed, as is the definition of hypokalemia. "Hypokalemia" may be present with a serum potassium value within the reference range of 3.5-5.0 mmol/l. Although diuretics are the most common cause of hypokalemia in patients with cardiac decompensation, there are other factors at work. One is an increase of the plasma aldosterone concentration and another the increased sympathetic nervous activity--adrenaline administration reduces the plasma potassium concentration. The clinical importance of hypokalemia, especially for cardiac arrhythmias, is discussed.