Background: The cardiopulmonary exercise test (CPET) is used in heart failure in order to
evaluate the symptoms, determine the differential diagnoses of dyspnea, consider the prognosis and
survival in diseases and finally help the patient's treatment. The aim of present study was to determine
the correlation between CPET results and the functional class of patients with advanced heart failure
candidate for heart transplantation.
Methods: A cross-sectional study was conducted in the respiratory department of Imam Khomeini
Hospital in Tehran (2016-2017). Total 86 patients (68 males and 18 females) who were candidates for
cardiac transplantation were entered in this study without any history, physical examination and
pulmonary functional test in favor of lung disease. The functional class was determined according to
NYHA classification, and ejection fraction calculated by trans-thoracic echocardiography. The cardiopulmonary
exercise test (CPET) was performed based on Bruce protocol and Gonshorn's
ergospirometer cycle apparatus. All necessary information was analyzed including BMI, Heart rate at
rest and Maximal activity, FEV1, FVC, FEV1/FVC, MEF 25-75, O2Saturation at rest and Maximal
activity, AT, peak VO2, WR, VE Max, VT Max VD/VT, respiratory rate, pet CO2, RER, VE/VCO2,
ventilatory reservation, functional class, test termination causes and Ejection fraction. The relationship
between functional class and CPET parameters was determined based on obtained results.
Findings: To sum up, the most common cause of test termination was shortness of breath and
generalized fatigue. The relationship between peak Vo2 and the functional class was significant and
inverse (P = 0.03). The VE/VCO2 at AT and the functional class were related considerably and
directly (p = 0.001).
Conclusion: This study showed that the higher grade of functional class in patients is correlated to
decline in peak Vo2 and increase in VE/VCO2 ratio at AT. Therefore, VE/VCO2 ratio, that is not
dependent on the patient's effort, is recommended in determination of prognosis and survival in
patients with heart failure.