[Cardiopulmonary exercise testing for the evaluation of unexplained dyspnea]

Dyspnea during exertion is a frequent and unspecific symptom. Tests performed at rest may yield abnormalities in both cardiac and pulmonary function but cannot reliably predict the exercise response. Cardiopulmonary exercise testing (CPET) using gas exchange techniques provides a global assessment of the exercise response, and it is the accepted gold-standard for the evaluation of unexplained dyspnea. The strengths of CPET include exact quantification of exercise capacity by measurement of oxygen uptake at peak exercise, the measurability of patient's effort, and the fact that CPET allows identification of the most important factor underlying a patient's exercise intolerance and dyspnea. This review article summarizes the basic principles of CPET for the evaluation of unexplained dyspnea.