Exercise Performance in Adolescents with Autonomic Dysfunction

• Published in: The Journal of pediatrics Vol. 158; no. 1; pp. 28 - 19.e1
• Main Authors: Burkhardt, Barbara E.U., MD, Fischer, Phil R., MD, Brands, Chad K., MD, Porter, Co-burn J., MD, Weaver, Amy L., MS, Yim, Paul J., BA, Pianosi, Paolo T., MD
• Format: Journal Article
• Language: English
• Published: Maryland Heights, MO Mosby, Inc 2011; Elsevier
• Subjects: Adolescent; adolescents; Autonomic Nervous System Diseases - complications; Autonomic Nervous System Diseases - physiopathology; Biological and medical sciences; Exercise; exercise test; Female; General aspects; head; heart rate; Humans; Male; Medical sciences; patients; Pediatrics; Postural Orthostatic Tachycardia Syndrome - complications; Postural Orthostatic Tachycardia Syndrome - physiopathology; Retrospective Studies; Tilt-Table Test; Heart rate; Postural orthostatic tachycardia syndrome; Head-up tilt; SV; HUT; SVI; Stroke volume index; HR; POTS; V o 2; Oxygen uptake; Stroke volume; Human; Performance evaluation; Physical exercise; Pediatrics; Dysfunction; Adolescent; Performance
• ISSN: 0022-3476; 1097-6833
• DOI: 10.1016/j.jpeds.2010.07.020

Objective To test the hypothesis that excessive postural tachycardia is associated with deconditioning rather than merely being an independent sign of autonomic dysfunction in patients with postural orthostatic tachycardia syndrome (POTS). Study design We retrospectively analyzed records from 202 adolescents who underwent both head up-tilt and maximal exercise testing. Patients were classified as POTS if they had ≥30 min−1 rise in heart rate (HR) after tilt-table test; and deconditioned if peak O2 uptake was <80% predicted. Changes in HR during exercise and recovery were compared between groups. Results Two-thirds of patients were deconditioned, irrespective of whether they fulfilled diagnostic criteria for POTS, but peak O2 uptake among patients with POTS was similar to patients without POTS. HR was higher at rest and during exercise; whereas stroke volume was lower during exercise, and HR recovery was slower in patients with POTS compared with patients without POTS. Conclusions Most patients who presented with chronic symptoms of dizziness, fatigue, or pre-syncope, were deconditioned, but, because the proportion of deconditioned patients was similar in POTS vs non-POTS groups, we conclude that HR changes in POTS are not solely because of inactivity resulting in deconditioning.