Serum magnesium concentrations in atrial fibrillation.

Serum magnesium and digoxin levels were obtained in 13 nontoxic patients with atrial fibrillation due to chronic rheumatic heart disease receiving digoxin for the control of ventricular rate and heart failure. Fairly good correlations were made between serum digoxin levels and ventricular rates. Hypomagnesemia was quite common (7 out of 13) and mean magnesium serum levels were significantly lowered in total as well in 7 hypomagnesemic patients, as compared to in healthy controls. Magnesium sulphate was successfully used in patients with magnesium deficiency to control the ventricular rates.