Hypercapnia and Orthostatic Tolerance in Postural Orthostatic Tachycardia Syndrome
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-60
SponsorUniversity of Calgary
About this trial
The mechanism behind postural orthostatic tachycardia syndrome (POTS) involves many causes including a sympathetic nervous system problem. Blood gases, like carbon dioxide (CO2), have an important effect on sympathetic activation.
The purpose of this research study is to determine if higher CO2 levels have any effect in lowering heart rate and reducing POTS symptoms when upright/standing. The investigators are also searching for the ideal CO2 concentration to achieve the most effective response
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Physician diagnosis of Postural Tachycardia Syndrome (POTS)
Age 18-60 years
Male and Female
Non - smokers.
Disqualifiers
Overt cause for postural tachycardia, i.e., acute dehydration
Participants with somatization or severe anxiety symptoms will be excluded
Pregnant
Inability to tolerate mask for the duration of the study
Trial design
Design model
Single group
Treatments tested in this trial
RespirAct™ system (Thornhill Research Inc., Toronto, Canada)
Other intervention1. HUTT with Normal Breathing in Room Air (No gas interventions will be applied) 2. HUTT with Normal Breathing and ETCO2 clamped at baseline levels 3. HUTT with Normal Breathing and Mild Hypercapnia (the ETCO2 will be clamped at 45mmHg ) 4. HUTT with Normal Breathing and High Hypercapnia (the ETCO2 will be clamped at 55mmHg) 5. HUTT with Fast, Deep Breathing and resultant Hypocapnia Participant will be coached to breath around 15 breath per min.No gas interventions will be applied 6. HUTT with Fast, Deep Breathing and ETCO2 clamped at baseline levels. Participant will be coached to breath around 15 breath per min, with ETCO2 clamped to baseline levels.
Treatment groups
26 Participants
are divided into 1 treatment groupGroup A: All participantsOther 1 intervention
Trial outcomes
Primary outcomes
1
Heart Rate (HR) variation
Magnitude of ΔHR
Time frame
difference between HR from supine to peak HR during tilt test for each intervention (mean value HR between the 8th and 9th minute of supine; peak parameters, during HUTT, mean value during the first min and between the 3rd and 8th min)Secondary outcomes
1
Cerebral blood flow velocity (CBFv) variation
Magnitude of ΔCBFv
Time frame
difference between CBFv from supine to peak during tilt test for each intervention (mean value CBFv between the 8th and 9th min of supine; peak parameters, during HUTT, mean value CBFv during the first min and between the 3rd and 8th min)2
VOSS symptom score
Vanderbilt Orthostatic Symptoms Score (VOSS) - patients will rate the severity of 9 symptoms on a scale of 0 to 10 (0 reflects absence of symptoms). The sum of the scores at each time point is used as a measure of symptom burden (lower score reflects reduced symptom burden). The 9 symptoms are mental clouding, blurred vision, shortness of breath, rapid heartbeat, tremulousness, chest discomfort, headache, lightheadedness, and nausea.
Time frame
VOSS will be accessed at the 8th minute of each HUTT, comparing the intensity of symptoms in each interventionSponsors and contacts
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Source ClinicalTrials.gov