[ECG changes and serum-digoxin concentration in digitalis toxicity (author's transl)].

Seventy-six patients with clinical and ECG evidence of digitalis toxicity and serum-digoxin concentrations over 2.5 ng/ml were investigated for possible correlation between certain ECG changes and the level of serum digoxin, but no correlation was found. However, radioimmunological determination of digoxin level proved to be a reliable means of deciding whether abnormalities of impulse formation or conduction were due to digitalis. In only one case (during haemodialysis) was there a fall in potassium level below normal, with signs of digitalis toxicity electrocardiographically. In five other patients with serum digoxin levels above 6 ng/ml high potassium values were found. Caution in the administration of potassium is advised: it should be given only if it is demonstrated to be below normal. Fifty-one of the patients had impaired renal function.