[Effect of prazosin in therapy-resistant chronic cardiac failure (author's transl)].

In addition to standard treatment with digitalis and diuretics prazosin (20 mg/d) and placebo were given to 14 patients with chronic therapy-resistant cardiac failure mainly of stage III for periods of 6 weeks each. Cardiac frequency, blood pressure, cardiac volume, pulmonary artery pressures and cardiac minute volume were assessed at rest and during physical exercise. Body weight, congestive changes in the chest radiograph, oedema and complaints were evaluated. During the acute trial using 2 mg of prazosin a significant increase of cardiac minute volume was demonstrable at rest and during exercise (2 P less than 0.05). After administration for 6 weeks cardiac minute volume increased from 3.2 to 4.0 l/min at rest and from 6.9 to 8.0 l/min during exercise (2P less than 0.005; n=12). There was a noticeable decrease of cardiac size from 1440 to 1306 ml/1.73 m2 (2 P less than 0.02). Haemodynamic improvement paralleled the decrease of complaints which was equivalent to an improvement of half to one stage of the New York Heart Association. In severe cardiac failure prazosin has thus an additional therapeutic effect beyond digitalis and diuretics.