Assessment of symptoms and exercise capacity in cyanotic patients with congenital heart disease.
OBJECTIVE
Patients with cyanotic congenital heart disease are generally thought to be limited by hypoxemia. To correlate exercise tolerance to the severity of the cardiac abnormality and to further characterize dyspnea in affected patients, we examined 25 adults with uncorrected cyanotic congenital heart disease.


METHODS
Cohort study at a university hospital.


METHODS
Symptom-limited cardiopulmonary exercise testing (CPX) was performed on a treadmill. Expiratory gas was analyzed breath by breath for evaluation of maximal exercise performance, ventilation, and ventilatory efficiency in combination with blood gas analysis during rest and exercise. Symptoms were assessed by the ability index and New York Heart Association class, and the results were compared to 101 healthy volunteers.


RESULTS
PaO(2) decreased by 26 +/- 8% (mean +/- SD) with exercise (from 49 +/- 12 to 36 +/- 10 mm Hg), while PaCO(2) was only slightly decreased compared to control subjects. Peak oxygen uptake (O(2)) was significantly reduced when compared to control subjects: 16.7 +/- 6.6 mL/kg/min vs 36.1 +/- 7.7 mL/kg/min. Ventilatory efficiency was markedly impaired at rest (minute ventilation [E]/carbon dioxide output [CO(2)] ratio of 70 +/- 18; control subjects, 53 +/- 11; p < 0.005) and during exercise (E vs CO(2) slope, 58 +/- 31; control subjects, 26 +/- 4; p < 0.005). At rest, ventilatory efficiency was correlated to resting pH and PaO(2), while during exercise it was linked to PaO(2). Ventilatory efficiency during exercise had the strongest correlation with observed symptoms, while hypoxemia and peak O(2) were not significantly associated with symptomatic state.


CONCLUSIONS
CPX in patients with cyanotic congenital heart disease provides helpful parameters that better define the symptomatic state of these patients. The summation of disease-related factors is best reflected by ventilatory efficiency. This parameter offers additional and independent information when compared to peak O(2) and the extent of cyanosis alone.
Gläser
Sven
S
Department of Medicine and Infectious Diseases, Charité Medical School, Humboldt University of Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany. Sven.Glaeser@Charite.de
Opitz
Christian F
CF
Bauer
Ulrike
U
Wensel
Roland
R
Ewert
Ralf
R
Lange
Peter E
PE
Kleber
Franz Xaver
FX
D000293:Adolescent; D000328:Adult; D015308:Anaerobic Threshold; D001784:Blood Gas Analysis; D016022:Case-Control Studies; D015331:Cohort Studies; D003490:Cyanosis / Q000150:complications / Q000175:diagnosis; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006330:Heart Defects, Congenital / Q000150:complications / Q000175:diagnosis*; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D011336:Probability; D011659:Pulmonary Gas Exchange; D012016:Reference Values; D018570:Risk Assessment; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric