Chest
Volume 125, Issue 2, February 2004, Pages 368-376
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Clinical Investigations
CARDIOLOGY
Assessment of Symptoms and Exercise Capacity in Cyanotic Patients With Congenital Heart Disease

https://doi.org/10.1378/chest.125.2.368Get rights and content

Objectives

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.

Design and setting

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

Pao2 decreased by 26 ± 8% (mean ± SD) with exercise (from 49 ± 12 to 36 ± 10 mm Hg), while Paco2 was only slightly decreased compared to control subjects. Peak oxygen uptake (

o2) 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 [
co2] ratio of 70 ± 18; control subjects, 53 ± 11; p < 0.005) and during exercise (
e vs
co2 slope, 58 ± 31; control subjects, 26 ± 4; p < 0.005). At rest, ventilatory efficiency was correlated to resting pH and Pao2, while during exercise it was linked to Pao2. Ventilatory efficiency during exercise had the strongest correlation with observed symptoms, while hypoxemia and peak
o2 were not significantly associated with symptomatic state.

Conclusion

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

o2 and the extent of cyanosis alone.

Section snippets

Patients

Twenty-five consecutive cyanotic patients with uncorrected congenital heart disease (12 women and 13 men) aged 18 to 59 years (mean age, 31 years; mean weight, 59 ± 12 kg; mean height, 171 ± 10 cm) underwent CPX. The study group consisted of patients treated in the outpatient clinic for congenital heart disease at the University Hospital Charité.

Two patients (patient 12/13 and patient 23/24) underwent evaluation twice with an interval of at least 6 months. Both patients were surgically

Symptomatology and Exercise Gas Exchange

Eighteen patients were assigned to NYHA class II, 8 patients to NYHA class III, and 1 patient to NYHA class IV. Ability classification was II in 6 patients, III in 17 patients, and IV in 4 patients. Seven patients were unable to work professionally; the remaining 20 patients were able to do so with limitations (avoiding physical labor).

The changes in ventilatory parameters and differences in exercise capacity as compared to normal values are given in Table 2. The maximal aerobic capacity was

Symptomatology and Exercise Gas Exchange

Patients with cyanotic congenital heart disease are generally thought to be limited by hypoxemia. Dyspnea, limited exercise capacity, lifestyle, and employment status are relevant factors for comprehensively evaluating the health of these patients. Consequently the ability index represents a supplemental tool in judging symptomatology.12 In this study, all patients stated an impaired quality of life. However, despite the severity of the cardiac malformations and the extent of cyanosis, 60% of

Conclusion

In cyanotic patients with congenital heart disease, CPX with gas exchange analysis provides additional and independent information, permitting more accurate and objective evaluation of their symptomatic state. In our patients, cyanosis and

e alone did not accurately reflect the symptomatic state. Peak
o2 did partially correlate with it, but was not able to describe the entire spectrum of symptoms as judged by the ability index and NYHA class.

Overall, the summation of disease-related factors is

ACKNOWLEDGMENT

We thank Karlman Wasserman, MD, PhD, Harbor-UCLA Medical Center, Torrance, CA, for his remarks and discussion of the manuscript.

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    The work was performed at the Department of Medicine, Charité Medical School Humboldt University of Berlin, Berlin, Germany.

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