Postural Sway and Counterpressure Maneuvers for Pediatric Syncope

The investigators are interested in whether discrete counterpressure maneuvers, or muscle movements in the lower body, will boost blood pressure and cardiovascular control in children who faint. We will record cardiovascular responses to maneuvers of exaggerated sway, leg crossing, crouching, and gluteal muscle tensing in children who faint (N=20), as well as their height, weight, muscularity, and pubertal (Tanner) stage. Autonomic cardiovascular control will be measured using a Valsalva manoeuvre (expiration against a closed airway for 20 seconds) and a supine-stand test. The primary outcomes are noninvasive measures of cardiovascular responses to the maneuvers (blood pressure, cerebral blood flow, and stroke volume (volume of blood pumped per heartbeat). Comparisons will be made across levels of sex, diagnosis, Tanner stage, muscularity, height, and degree of autonomic control.

NCT Number	NCT05633693
Lead Sponsor	Simon Fraser University Collaborators: Provincial Health Services Authority British Columbia, University of British Columbia, Natural Sciences and Engineering Research Council, Canada
Conditions	Syncope, Vasovagal, Postural Orthostatic Tachycardia Syndrome, Orthostatic Intolerance
Enrollment	30 participants
Start Date	2023-04-17
Primary Completion	2027-05 (estimated)
Study Completion	2027-06 (estimated)
Updated on ClinicalTrials.gov	2026-04-23