Abstract P041: Impaired Autonomic Control of Heart Rate at Rest and Slower Post-exercise Heart Rate Kinetics in Children with Congenital Heart Defects

Introduction: A slow recovery in heart rate (HR) following exercise is due to autonomic dysfunction and is associated with increased cardiovascular event risk. Children with congenital heart defects (CHD) display autonomic dysfunction as shown by a reduction in HR variability (HRV). Whether children with CHD have impairment in post-exercise HR recovery is unknown. Hypothesis: We tested the hypothesis that children with CHD would have reduced HRV at rest and slower HR recovery kinetics following 6-minute walk testing (6MWT) compared to healthy controls. Methods: Twenty-five children with CHD (11±2 years; males=14; females=11) and 21 age- and sex-matched controls (11±3 years; males=10; females=11) were studied. CHD diagnoses included Tetralogy of Fallot (n=7), pulmonary or aortic stenosis (n=3), hypoplastic left or right heart syndrome (n=5), Ebstien’s anomaly (n=1), atrial or ventricular septal defect (n=3), transposition of the great arteries (n=1), double inlet left ventricle (n=1), tricuspid atresia (n=...