[Blood digoxin and treatment of heart failure in aged patients].

Serum digoxin level was determined by radioimmunoassay in 76 elderly in-patients (age: 76.1 +/- 1.0) which were treated by digoxin without any evidence of toxicity. Digoxin levels was related to blood nitrogen (p less than 0,01); on the other hand, no relationship between others factors influencing the digoxin bioavailability (age, body weight, associated drug) and digoxin levels could be found. Therapeutic effectiveness, as estimated by ventricular rate and signs and symptoms, was not dependent of digoxin levels. In patients with higher functional class (III and IV NYHA), however, digoxin level was generally demonstrated to be increased. Digoxin levels were lower in patients with coronary heart disease (1.71 +/- 0,22 ng/ml; n = 16) than in patients with right ventricle overload (2.94 +/- 0,74 mg/ml; n + 7 - p less than 0.05). Because of the very large scattering of digoxin levels, digoxin determination seems to be useful in measuring individual bioavailability and therapeutic effectiveness, and leading to the best base line of any individual treatment.