Research

The Pathophysiological Role of Adrenergic Antibodies in POTS

A pilot study involving autonomic function testing (AIM #1), small doses of short acting medications (AIM #2), and a longer medication trial (AIM #3) to evaluate the role of antibodies in cardiovascular regulation in POTS patients as compared to healthy volunteers. POTS participants are invited back for follow-up examination one year following the study. All participants are required to complete an online questionnaire. 

More Information

A Randomized Crossover Study of Propranolol versus Ivabradine in POTS

There are currently no approved medicinal treatments for patients with POTS. We aim to examine the differences between Ivabradine and Propranolol in these patients to determine a medication that can be accepted as a treatment for POTS. We are looking not only at the hemodynamic responses but also the quality of life these patients endure while on each medication.

More Information

Multicentre Assessment of Cardiovascular Hemodynamics and Autonomic Dysfunction with Long-COVID

This study aims to determine how the control mechanisms of the heart and circulation are working post-COVID-19 infection. “Autonomic nerves” help to regulate control of blood pressure, heartbeat and circulation in response to “stressors” like standing or exercising. In some people, these nerves may not work properly, which can cause abnormal heart rate or blood pressure responses. In this study, we test cardiovascular autonomic control in patients with ongoing symptoms late post-COVID-19 infection to see if things are not functioning well in patients with these symptoms.

CAlgary SAlt for POTS (CASA-POTS) Study

86% of POTS patients have a low plasma volume. Current POTS guidelines recommend 10 g of salt and 2-3 L of daily fluid. Currently, evidence shows the benefits of supplemental salt intake over one week. We are conducting a long-term randomized-clinical cross-over study trial to assess the effects of dietary salt. This study aims to see if increasing the amount of salt in the diet will reduce heart rate and symptoms in patients with POTS or with post-COVID-POTS when compared to a placebo. This is a cross-over study, in which participants will do both the high-salt and moderate-salt components. 

More Information

Investigating Chest Pain and Heart Health in Patients with POTS

POTS is a condition characterized by a fast heart rate when standing, often accompanied with chest pain. Unfortunately, patients often get told that their chest pain is “all in their heads.” This study aims to identify the cause of chest pain in POTS using cardiac magnetic resonance imaging (CMR). Patients also have concerns about whether their fast heart rate and chest pain impact their long-term heart health. We will use CMR to check for heart damage. If we discover problems in the heart, patients with POTS may benefit from protective treatments to prevent further heart damage.

Neurocognitive Testing in Long-COVID and POTS Patients with Normal Saline: A Pilot Study

95% of POTS patients report cognitive impairment. Many individuals who have Long Covid (LC) also experience cognitive impairment. In this study, we aim to investigate the impact of normal saline on brain fog in POTS and LC participants. We hypothesize that measures of neurocognitive functions will improve in POTS and LC participants after infusion of normal saline. We will test our hypothesis using a double-blinded, randomized, placebo-controlled cross-over study. This study provides an initial first step toward understanding neurocognitive impairment in participants with LC and POTS.

More Information

CO2 Rebreathing to increase Blood Pressure in Neurogenic Orthostatic Hypotension: A Proof-of-Concept Pilot Study

Neurogenic orthostatic hypotension (nOH) is a debilitating condition that results in a decrease in blood pressure when changing posture. nOH is caused by a failure of the autonomic nervous system to control the sympathetic nervous system. Previous studies have shown that hypercapnia can be a method of increasing blood pressure. This study aims to provide a proof of concept for a simple, cost-effective rebreather device to correct nOH. By recapturing exhaled CO_2, this device could increase arterial CO₂ sufficiently to correct a rapidly falling blood pressure and prevent syncope.

Assessment of the Relationship Between Cerebral Blood Flow and Heart Rate: An Electrophysiology Based Study

Cerebral blood flow (CBF) is an important concept in POTS or syncope. Patients who experience reduced CBF often experience symptoms of presyncope and may even faint (syncope). To investigate the relationship between heart rate and CBF, we collect a transcranial doppler (TCD) signal on patients undergoing operations where a temporary pacing catheter is placed in their right atrium. The heart is paced at 4 different speeds during the procedure, and the resulting CBF is measured. This study aims to understand the physiological mechanism behind chronic presyncope symptoms. 

Role of Posture vs. Tidal Volume vs. Carbon Dioxide on Heart Rate and Symptoms in Patients with POTS

Postural hyperventilation is a complex clinical phenomenon integrating postural changes, increased breathing depth (tidal volume) and reduced arterial carbon dioxide (CO₂; hypocapnia). Postural hyperventilation worsens tachycardia and symptoms in POTS. Hypocapnia reduces brain blood flow which could lead to symptoms. A potential novel solution to counter the effects of POTS may be to increase the amount of inspired CO₂. The study's overall objective is to determine possible therapeutic targets to manage HR and symptoms in patients with POTS and investigate novel therapeutic management options.

Prevention of Syncope Trial VII (POST 7)

In this study, we will test the hypothesis that oral atomoxetine prevents syncope in patients with recurrent vasovagal syncope (VVS). Patients will be included based on a positive Calgary Syncope Symptom Score and a history of at least 2 faints in the previous year. Eligible patients will be randomized to 40 mg atomoxetine twice daily or matching placebo in a randomized, placebo-controlled, parallel design, double-blind, crossover trial.

Prevention of Syncope Trial X (POST 10)

In this study, we will test the hypothesis that the strategy of first conducting a tilt table test will provide an earlier diagnosis at less cost as opposed to first implanting an ICM. A total of 116 syncope patients at least 50 years of age will be randomized to an initial strategy of tilt testing or receiving an ICM. The primary outcome measure will be the establishment of a documented etiologic diagnosis of the cause of syncope. 

Prevention of Syncope Trial XI (POST 11)

In this study, we will test the hypothesis that pharmacological 5HT3 inhibition by ondansetron will increase tilt test tolerance prior to syncope in patients with recurrent vasovagal syncope (VVS). This study is a randomized, double-blind, parallel-arm study in which the subjects will undergo a tilt table test following 2 doses of 8 mg of ondansetron. On the morning of the study the participant will have 12-lead ECG, tilt table test, segmental bioelectrical impedance (BEI) and Inferior Vena Cava Ultrasound.