Recently, the number of patients with congenital heart diseases reaching adulthood has been progressively increasing in developed countries and new issues are emerging regarding them: the evaluation of their capacity to cope with physical activity, and whether this knowledge can be used to optimize medical management. A symptom-limited cardiopulmonary exercise test has proven to be an essential tool because it can objectively evaluate the functional cardiovascular capacity of these patients, identify the pathological mechanisms of the defect (circulatory failure, shunts, pulmonary hypertension) and help prescribe an individualized rehabilitation program when needed. The common findings on cardiopulmonary exercise testing in patients with congenital heart diseases are a reduced peak oxygen uptake, an early anaerobic threshold, a blunted heart rate response, a reduced rise of tidal volume, and an increased ratio of minute ventilation to carbon dioxide production. All these measures suggest common pathophysiological abnormalities 1) a compromised exercise capacity from anomalies affecting the heart, vessels, lungs or muscles, 2) chronotropic incompetence secondary to cardiac autonomic dysfunction or beta-blockers and antiarrhythmic therapy, and 3) ventilatory inefficiency caused by left-heart failure with pulmonary congestion, pulmonary hypertension, pulmonary obstructive vascular disease or cachexia. Most of these variables have also prognostic significance. For these patients, cardiopulmonary exercise testing allows evaluation and decisions affecting life-style and therapeutic interventions.
Mantegazza V, Apostolo A, Hager A. Cardiopulmonary Exercise Testing in Adult Congenital Heart Disease. Ann Am Thorac Soc 2017 Apr 4. doi: 10.1513/AnnalsATS.201611-876FR