Digoxin and xamoterol in patients with moderate chronic heart failure. A double-blind, randomized, controlled study

Xamoterol is a partial beta 1 adrenoceptor agonist with positive inotropic properties. Treatment with xamoterol and digoxin was compared in 19 patients with cardiac failure (NYHA class II-III). The study consisted of a short-term and a long-term phase. The former was a randomized, double-blind, crossover study with 6-week treatment periods. In the 15 patients who completed this phase, there was no significant difference between exercise duration on digoxin and on xamoterol. Exercise duration increased on digoxin by 27% and on xamoterol by 17% relative to baseline. Comparing digoxin and xamoterol, maximum exercise heart rate (p less than 0.001), blood pressure (p less than 0.01), and the pressure-rate product during maximum exercise were significantly lower on xamoterol treatment. The systolic time interval was shorter on digoxin than on xamoterol (p less than 0.001). No changes occurred in the echocardiographic parameters. After the short-term study, 13 patients were followed 3-6 months on the drug to which they had responded best (digoxin 7, xamoterol 6). The results of the short-term study were maintained during this period. In conclusion, we found that xamoterol may be an alternative to digoxin in patients with mild to moderate heart failure.