Actively Recruiting
The Pathophysiological Role of Adrenergic Antibodies in Postural Tachycardia Syndrome (Aims #1&2)
Led by University of Calgary · Updated on 2026-05-05
125
Participants Needed
1
Research Sites
52 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Researchers are investigating Postural Tachycardia Syndrome (POTS), a condition causing a rapid heart rate increase when standing and symptoms like palpitations, lightheadedness, and mental clouding. This study tests the idea that POTS patients aged 18 to 60 have more functional antibodies against adrenergic receptors compared to people without POTS. The research aims to understand the prevalence of these antibodies and their relationship to autoimmune illnesses and patient symptoms. Participants include POTS patients and healthy volunteers matched by age and gender. Both groups receive intravenous injections of phenylephrine and isoproterenol in small increasing doses. Researchers observe the blood pressure and heart rate responses to find the doses that raise systolic blood pressure or heart rate by 25 units respectively. This helps evaluate the physiological effects of adrenergic antibodies in living humans. During the study, participants undergo careful monitoring of heart rate and blood pressure through continuous measurements after each drug dose. Researchers record peak responses and wait for values to return to baseline before increasing doses. The main outcome measured is the proportion of subjects positive for alpha-1 adrenergic antibodies after one year. Secondary outcomes include antibody positivity by various clinical factors and the dose responses to the drugs. The total study period is one year with detailed assessments throughout.
CONDITIONS
Brief Title
POTS Adrenergic Ab (CIHR Aims #1&2)
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Patients previously diagnosed with Postural Tachycardia Syndrome (POTS)
- Control subjects without a POTS diagnosis
- Age between 18 and 60 years
- Male and female participants
- Able and willing to provide informed consent
You will not qualify if you...
- Current smokers
- Acute dehydration or other overt causes of postural tachycardia
- Significant cardiovascular, pulmonary, hepatic, or hematological disease
- Highly trained athletes
- Severe anxiety symptoms or somatization
- Use of drospirenone-containing oral contraceptives
- Hypertension with resting blood pressure over 145/95 mmHg off medications or requiring antihypertensive drugs
- Any condition preventing completion of the study protocol, including poor compliance or unpredictable schedules
- Unable to give informed consent
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - Single day
Participants receive incremental small doses of intravenous phenylephrine and isoproterenol while heart rate and blood pressure are continuously monitored to determine the dose that causes specified cardiovascular responses.
1 in-person visit with sequential drug dosing and monitoring
Duration - Up to 1 year
Participants are observed with antibody assays performed over a period of up to 1 year to assess adrenergic antibody levels and related outcomes.
Periodic blood sample collections during the year
Trial Site Locations
Total: 1 location
1
University of Calgary
Calgary, Alberta, Canada, T2N 4Z6
Actively Recruiting
Research Team
S
Satish R Raj, MD, MSCI
R
Robert S Sheldon, MD, PhD
How is the study designed?
Study Type
OBSERVATIONAL
Masking
N/A
Allocation
N/A
Model
N/A
Primary Purpose
N/A
Number of Arms
2
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