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 30.6%; mean age, 68 years).


RESULTS
The severity of dyspnea at peak exercise, which patients rated as 3 to 10 on a 1 to 10 severity scale, did not correlate with rest or exercise hemodynamic, spirometric, or metabolic variables, including peak oxygen uptake (VO2), minute ventilation (Ve), and respiratory rate, or with derived variables including Ve/VO2, Ve/VCO2, and the dyspnea index (Ve/maximum voluntary ventilation). Additionally, these variables did not differ between patients who reported limitation of exercise by dyspnea and those who were limited by fatigue.


CONCLUSIONS
The symptom of exertional dyspnea in patients with heart failure is not determined by abnormalities in ventilatory function or demand.
Russell
S D
SD
Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
McNeer
F R
FR
Higginbotham
M B
MB
D000368:Aged; D000369:Aged, 80 and over; D004417:Dyspnea / Q000503:physiopathology*; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D011659:Pulmonary Gas Exchange; D012119:Respiration; D012129:Respiratory Function Tests; D013147:Spirometry