Reduced cerebral blood flow with orthostasis precedes hypocapnic hyperpnea, sympathetic activation, and postural tachycardia syndrome.
Andrew T Del Pozzi, Christopher E Schwartz, Deepali Tewari...
https://pubmed.ncbi.nlm.nih.gov/24711524Actively Recruiting
Phase Not Applicable
Age: 18Years - 60Years
All Genders
ID04271878
Hypercapnia and Orthostatic Tolerance in Postural Orthostatic Tachycardia Syndrome
Led by University of Calgary · Updated on 2026-05-07
26
Participants Needed
1
Research Sites
52 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Postural orthostatic tachycardia syndrome (POTS) involves various causes, including issues with the sympathetic nervous system. This research aims to see if higher levels of carbon dioxide (CO2) can lower heart rate and reduce POTS symptoms when standing. The study also seeks to find the ideal CO2 concentration for the best response. Participants will use the RespirAct™ system, a device that controls the gases they breathe to adjust blood CO2 levels. The study includes several tilt table tests (HUTT) with different breathing conditions, including normal breathing, mild and high hypercapnia (increased CO2), and fast, deep breathing. All participants receive the same interventions using a face mask connected to the RespirAct™ system. During the study, participants will be monitored for heart rate changes, cerebral blood flow, and symptom intensity during each tilt test. Data on gas concentrations, breathing rate, and volume will be recorded breath-by-breath. The study also includes safety monitoring for adverse events and keeps participant information confidential. The main measure is heart rate variation during tilt tests, with follow-up lasting through all interventions.
CONDITIONS
Brief Title
Hypercapnia and Orthostatic Tolerance in Postural Orthostatic Tachycardia Syndrome
Who Can Participate
Age: 18Years - 60Years
All Genders
Eligibility Criteria
You may qualify if you...
- Physician diagnosis of Postural Tachycardia Syndrome (POTS)
- Age 18 to 60 years
- Male and Female
- Non-smokers
- Able and willing to provide informed consent
- Ability to travel to the Libin Cardiovascular Institute of Alberta Autonomic Testing Lab at the University of Calgary
You will not qualify if you...
- Acute dehydration causing postural tachycardia
- Presence of somatization or severe anxiety symptoms
- Pregnant individuals
- Inability to tolerate mask for study duration
- Requirement for portable oxygen at rest or during exercise
- Chronic heart failure or severe pulmonary disease preventing climbing one flight of stairs due to shortness of breath
- Other factors that would prevent completing the protocol or poor compliance in previous studies
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
1
2
3
Your Study Journey
Screening
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Treatment
Duration - Single day procedure
Participants undergo a series of tilt tests (HUTT) with different breathing interventions using the RespirAct™ system to assess the effects of hypercapnia on heart rate and symptoms.
1 in-person visit with multiple tilt test sessions
Trial Site Locations
Total: 1 location
1
University of Calgary
Calgary, Alberta, Canada, T2N 4Z6
Actively Recruiting
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Research Team
S
Shaun Ranada, BSc
R
Rasha Hamza, RN
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
OTHER
Number of Arms
1
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Published Research Related To This Trial
Decreased upright cerebral blood flow and cerebral autoregulation in normocapnic postural tachycardia syndrome.
Anthony J Ocon, Marvin S Medow, Indu Taneja...
https://pubmed.ncbi.nlm.nih.gov/19502561Baroreceptor unloading in postural tachycardia syndrome augments peripheral chemoreceptor sensitivity and decreases central chemoreceptor sensitivity.
Indu Taneja, Marvin S Medow, Debbie A Clarke...
https://pubmed.ncbi.nlm.nih.gov/21536847Postural Hyperventilation as a Cause of Postural Tachycardia Syndrome: Increased Systemic Vascular Resistance and Decreased Cardiac Output When Upright in All Postural Tachycardia Syndrome Variants.
Julian M Stewart, Paul Pianosi, Mohamed A Shaban...
https://pubmed.ncbi.nlm.nih.gov/29960989Hypocapnic cerebral hypoperfusion: A biomarker of orthostatic intolerance.
Peter Novak
https://pubmed.ncbi.nlm.nih.gov/30256820