Exercise-induced hypoxemia and cardiac arrhythmia in cystic fibrosis

BackgroundPhysical activity has become part of the therapy of patients with cystic fibrosis (CF) despite possible risks. The objectives of this study were to identify predictors of hypoxemia and to search for cardiac arrhythmia during exercise.MethodsThe data of 75 patients (12 to 41 years old) with CF who underwent a standardized incremental exercise test on a cycle ergometer was analyzed. Oxygen saturation (SpO2) and ECG were monitored. The results were related to spirometric and SpO2 measurements at rest.ResultsDuring exercise, 17 patients suffered from significant desaturations (SpO2 < 90%). SpO2 at peak exercise was independently related to SpO2 at rest and 1/FEV1 (multiple regression R2 = 0.63). Five patients demonstrated ventricular arrhythmias during exercise. No unambiguous prediction of exercise-induced hypoxemia or cardiac arrhythmia was possible.ConclusionIn order to detect all patients with exercise-induced hypoxemia and cardiac arrhythmia, an incremental exercise test to volitional fatigue must be performed.