Exercise Intolerance in Pulmonary Arterial Hypertension. The Role of Cardiopulmonary Exercise Testing

A 23-year-old, never-smoking woman who was physically fit since childhood developed progressive intolerance to exertion in the preceding 12 months. She was diagnosed with severe pulmonary arterial hypertension due to an atrial septal defect and subsequently underwent cardiopulmonary exercise testing. An understanding of exercise physiology was essential in identifying the pathophysiological causes of her dyspnea on exertion and assessing the response to pharmacological therapy. A white, 23-year-old woman sought medical attention complaining of progressive exercise limitation due to shortness of breath and “fatigue,” which started about a year earlier. She denied cough, wheezing, or any other respiratory symptoms. She reported being physically active since childhood, but had become mildly limited during daily life activities (New York Heart Association Class II). She denied smoking, significant occupational or environmental exposures, use of illicit drugs, and exposure to drugs with known lung toxicity. She weighed 50 kg and her height was 157 cm.