An interventional study of Counterpressure Maneuvers and Usual Care in Syncope, Vasovagal, Postural Orthostatic Tachycardia Syndrome and Orthostatic Intolerance, sponsored by Dr. Victoria Claydon. Recruiting at 1 site in Canada. Open to participants aged 6 Years to 18 Years. Per ClinicalTrials.gov, last updated 2026-04-23.
Sponsored by Dr. Victoria Claydon · Not applicable, Interventional, and Treatment
The investigators will assess the efficacy of clinically recommended counterpressure maneuvers (CPM) in preventing syncope for paediatric patients. Participants presenting to the emergency department (ED) will first provide written informed consent. In stage I, they will be asked to complete a brief survey documenting the presentation of their syncopal episode, and any prodromal symptoms they experienced. Participants that consent to the second stage of the study will either receive usual care (control arm) or training in counter pressure maneuvers alongside usual care (intervention arm; leg crossing, bending, arm tensing). These patients will be followed for one years time, and will be asked to complete monthly surveys detailing their syncopal and presyncopal recurrence. Medical records will be accessed over the duration of the study to identify any changes in medical diagnosis.
Knowledge Gaps and Objectives The typical presentation and management for paediatric syncope is poorly understood. From research in adults, it is known that obtaining a detailed history of prodromal symptoms and the circumstance of a syncopal event is important for diagnosis, risk stratification, and determining patient prognosis. However, research in paediatric patients is lacking, with recommendations often disputed and based on a paucity of direct evidence, assuming that children will respond similarly to adults; however, this may not be the case. The investigators will (stage I) catalogue the syncopal symptoms observed in paediatric patients presenting to the emergency department (ED) with transient loss of consciousness, and (stage II) assess the efficacy of counter pressure maneuver (CPM) training in preventing recurrent syncope for paediatric patients.
Methods, Stage I; Presentation of syncope in paediatric patients Ethical approval for this study was granted by the University of British Columbia's Clinical Research Ethics Board. The investigators will recruit paediatric patients (age 7-19 years) presenting to the ED with resolved transient loss of consciousness in the last week. Research assistants will identify potential participants based on exclusion criteria, and a clinician will later gather a brief medical history and perform a screen for study eligibility. Exclusion criteria: suspected or confirmed cardiac arrhythmia diagnosis; traumatic head injury; new presentation of a seizure disorder or epilepsy; structural heart disease; hypoglycemia; physical and/or psychological disability associated with vasovagal syncope (VVS).
Consenting patients will complete a survey detailing the nature of their episodes in terms of the provocative situation, their signs and symptoms, and history of syncope or presyncope alongside a brief medical history (age, self-reported Tanner stage, age at onset of female menarche if applicable).
The primary outcome is to document the typical presentation of syncope and presyncope in paediatric patients identified as having experienced VVS. Additional outcomes include predictive factors for uncomplicated syncope in this population, including the influence of pubertal stage on the onset of paediatric syncope. Secondary outcomes include identifying the incidence of syncope, determining typical causes for syncope, and reporting on predictive factors for syncope secondary to other causes in this population. Bivariate analyses assessing possible associations between presenting prodromes and syncopal diagnoses will be conducted using either Fisher or Chi-square tests for categorical variables, and univariate multinomial models for continuous variables. These analyses will also be conducted adjusting for age and sex (either through regression or matching). The incidence and subtype of syncope presented will be calculated using an appropriate reference population. Qualitative data will be analyzed using a thematic approach, to identify trends in chosen variables based on patient responses.
Methods, Stage II; Paediatric counterpressure manoeuvres trial Stage I patients with a confirmed diagnosis of VVS from a clinician will be referred to stage II. Patients will be followed for one year while they implement either usual care for syncope (behavioural interventions and avoidance measures) or usual care alongside CPM use (leg crossing, hand grip, crouching). The primary outcome measure will be the time to syncopal reoccurrence over the 1-year follow up period, while secondary outcome measures include history of syncope in the prior 2 years, frequency of presyncopal episodes, preferred management strategies (CPM, or usual care), and barriers to implementing CPM. The predicted risk of syncopal reoccurrence will be identified using a logistic regression model with a covariate for treatment arm (CPM, standard of care). Outcomes will be compared between groups using the estimated risk ratio and risk difference. The Wald test for the log-odds coefficient from the logistic model will be used to test for treatment effect (level of 0.05). The investigators will also perform a Kaplan-Meier survival analysis (time to syncope recurrence), using a log-rank test and Cox proportional hazards analysis to compare curves. Qualitative follow-up call data will again be analyzed using a thematic approach.
88 studies on the registry are indexed under Syncope, Vasovagal; 28 are open to participants now.
This study's planned enrollment of 300 is above the median of 59 across 58 interventional studies indexed under Syncope, Vasovagal.
Browse Syncope, Vasovagal studies →This is the only study on the registry with Dr. Victoria Claydon as lead sponsor.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Those with a known history of any of the following:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will receive standard of care treatment (behavioural intervention and avoidance measures, as indicated in "Usual Care"), alongside training in counter pressure maneuvers. Training in counterpressure maneuvers will be delivered through a handout and video that will show three maneuvers (i.e. arm-tensing, squatting, and leg-crossing) that patients enrolled in the intervention arm can perform when they begin to experience common signs and symptoms of syncope. Patients will be instructed to start with one of the maneuvers and if their symptoms do not go away, move on to a second or third maneuver if needed.
Behavioral: Counterpressure Maneuvers
Participants will receive standard of care treatment for their diagnosis of syncope. This primarily includes behavioural interventions and avoidance measures (e.g., stay hydrated, increase salt intake, avoid hot situations, avoid standing for long periods of time, engage in regular physical activity). Some patients may be prescribed medication (Midodrine, Fludrocortisone) at the discretion of their physician.
Behavioral: Usual Care
Movements that can aid in delaying or preventing syncope by recruiting skeletal muscle pumping (via compression of major veins by contracting muscle to eject blood through cardiovascular circuit) and increased sympathetic drive (via sustaining an isometric muscle contraction). In this trial, we will be evaluating three commonly recommended maneuvers of arm tensing, squatting, and leg crossing with arm tensing. Maneuvers should be held for 1-2 minutes, or until symptoms subside.
Also known as: Physical counter maneuvers, counter maneuvers,
Participants will engage in behavioural interventions and avoidance measures that are commonly recommended as a part of usual care for recurrent syncope. This primarily includes recommendations such as staying hydrated, increasing salt intake, avoiding warm temperatures, avoiding standing for long periods of time, and engaging in regular physical activity. Some patients may be prescribed medication (Midodrine, Fludrocortisone), or other assistive interventions (e.g., compression stockings) at the discretion of their physician.
Number of patients with syncopal recurrence
Participant experiences an episode of syncope (transient loss of consciousness and postural tone followed by a spontaneous recovery) over the course of the one year follow up.
Time frame: One year, reported in monthly surveys.
Syncopal incidence
Report on the incidence of syncope in our cohort
Time frame: One year
Documentation of typical prodromal symptoms
Link the prodromal symptoms of the different types of syncope in the pediatric population with the final diagnosis after at least one year of follow-up.
Time frame: One year
Number of patients with exercise-related syncope
Determine the diagnosis of pediatric patients who may experience syncope that is temporally associated to exercise
Time frame: One year
Number of patients with syncope secondary to other causes
Report on predictive factors for syncope secondary to other causes
Time frame: One year
Plan to share: No
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