EFFECT OF CAPTOPRIL THERAPY ON LYMPHOCYTE POTASSIUM AND MAGNESIUM CONCENTRATIONS IN PATIENTS WITH CONGESTIVE-HEART-FAILURE

Lymphocyte potassium and magnesium were measured before and 3 months after the introduction of captopril in 18 patients taking diuretics for congestive heart failure. Compared to 32 healthy controls, 9 patients who had been on potassium supplements plus frusemide had decreased baseline lymphocyte magnesium and potassium concentrations (p < 0.01), in spite of similar plasma electrolyte levels. There was a significant (p < 0.01) increase in both lymphocyte potassium and magnesium levels after 3 months' treatment with captopril and frusemide in these patients. Nine patients who had been taking a potassium-sparing combination diuretic also had an increase in lymphocyte magnesium (p < 0.05) following the introduction of captopril. Increased intra-cellular potassium and magnesium may be one mechanism whereby angiotensin-converting enzyme inhibitors reduce arrhythmias and improve survival in patients with congestive heart failure.