Pediatric Cardiopulmonary Exercise Testing

18 patients performed a symptom-limited cardiopulmonary exercise test (CPET) on a bicycle ergometer (VIAsprint^® ergoselect 100 ergometer, ergoline GmbH, Bitz, Germany). The test implementation was adapted to the methods previously described by Pasquali et al. (14 (link)) Pedal length was adjusted according to the recommendations of the German society for pediatric cardiology (24 , 25 ). As recommended for children and adolescents, a weight-based protocol was used with a starting load of 1.0 W/kg body weight and an increase of 0.5 W/kg load every two minutes (24 , 26 (link)). The test was continued until limiting symptoms for exercise termination occurred, according to criteria previously described (27 (link)). For overweight children and adolescents, the workload was calculated corresponding to their height to avoid overloading (26 (link)). Respiratory gas exchange measurements were obtained breath by breath by a commercially available system (Vyntus^® CPX, Vyaire medical Inc., Mettawa, IL-USA). Peak oxygen uptake (VO2) was recorded as the mean value of VO2 during the last 20 s of the test. In addition, the respiratory volume per minute, the breathing rate per minute and the heart rate per minute were measured. All parameters were recorded at the start of the test (resting conditions) and continuously during the test. When the maximum workload was reached, the system was immediately resetted to the individual starting conditions and measurements were obtained for another two minutes. As recommended by the German society for pediatric cardiology, individual z-scores for participants ages 6 – 18 were calculated based on the reported data by Klemt et al. (28 , 29 ) For participants >18 years, the reference values reported by Gläser et al. from the SHIP-Study (30 (link)) were used.