Exertional dyspnea in heart failure: a symptom unrelated to pulmonary function at rest or during exercise. Duke University Clinical Cardiology Studies (DUCCS) Exercise Group.

Background: Exertional dyspnea is a common symptom in patients with heart failure, and the mechanisms responsible for the symptom are unknown. The purpose of this study was to identify factors responsible for the symptom of exertional dyspnea in patients with heart failure.

Methods: Resting pulmonary-function tests and maximal cardiopulmonary exercise tests were performed in 71 patients with New York Heart Association functional class II-IV symptoms (mean ejection fraction 30.

Improvement in the mechanical efficiency of walking: an explanation for the "placebo effect" seen during repeated exercise testing of patients with heart failure. Duke University Clinical Cardiology Studies (DUCCS) Exercise Group.

To determine the mechanism responsible for the "placebo effect" seen during serial exercise testing of patients with heart failure, we examined metabolic variables for 81 patients who underwent five baseline exercise tests as part of a multicenter drug trial. The patients were 50 men and 31 women with a mean ejection fraction of 30.1% and a mean age of 69 years.