Cardiopulmonary Exercise Testing is Safe in Children and Adolescents with Cardiomyopathy

Background Cardiopulmonary exercise testing (CPET) has been recommended in pediatric patients with hypertrophic cardiomyopathy (HCM); however, safety has not been well defined. Studies in adults with cardiomyopathy (CM) consistently show reduced maximal and submaximal exercise capacity and impaired ventilatory efficiency compared to matched controls, with mixed data in children. This single-center retrospective study aimed to identify differences in adverse events and exercise parameters in children and adolescents with CM versus matched controls. Methods From 2014 to 2023, 227 CPETs were completed in 141 patients with CM, ages 6 to 22 years. Only maximal CPETs were included for control-matched sub analysis, resulting in 113 tests in 83 CM patients. Subjects were matched with healthy controls based on sex, age, body mass index (BMI), body surface area (BSA), and stress exercise modality to evaluate for differences in heart rate (HR), systolic blood pressure (SBP), electrocardiogram (ECG) changes, incidence of adverse events (ischemia, SBP drop, and arrhythmias), exercise-induced symptoms, and peak exercise parameters. Results There were 4 CM tests (all HCM, 1.8%) terminated due to adverse events: SBP drop (2) and non-sustained ventricular tachycardia (2). Control patients reported significantly more symptoms of chest pain and dizziness with exercise. Maximal and submaximal oxygen consumption (VO 2 ), SBP, HR, and minute ventilation (VE) were lower in CM patients. Conclusion In our cohort, CPET testing in children and adolescents with CM was safe. Maximal and submaximal exercise capacity was reduced in CM patients, likely due to reduced cardiac output, with lower HR and VE at peak exercise. Future studies may identify if exercise parameters can be used to risk stratify patients or predict outcomes.