Jun 9

Jun 9 Postural Orthostatic Tachycardia Syndrome (POTS)

Summary

POTS stands for Postural Orthostatic Tachycardia Syndrome. It is a chronic syndrome, whose symptoms occur with changes in posture (postural) when going from lying down to an upright position (orthostatic).¹ During these changes, there is sustained increased heart rate (tachycardia) without significant changes in blood pressure.² POTS is part of a larger classification of syndromes related to chronic orthostatic intolerance syndromes. Orthostatic intolerance describes symptoms of lightheadedness, black-out, “brain fog” and abnormally rapid heartbeats.³ POTS is a complex syndrome with a range of symptoms, for which the causes are still debated. It requires careful diagnosis and individualized care.

Epidemiology

The prevalence of POTS in Canada is unknown, however, data suggest a prevalence of 0.01-1% of the total population in the United States.¹ Nevertheless, these numbers may not fully represent the actual number of people with POTS because there are misdiagnosed and undiagnosed patients. The presentation of POTS symptoms is more prevalent in females than males and may start in the early teens to adulthood.¹

Etiology and Pathology

The origin of POTS is still debated and might not be the same for each patient. It may be related to an abnormal cardiovascular (heart and blood pressure) regulation issue or a disorder that affects the whole body (systemic disorder).

Some of the possible causes of POTS include a decreased volume of circulating blood (hypovolemia), increased sustained adrenaline (hyperadrenergic stimulation), changes in the autonomic nervous system (autonomic dysfunction), and reduced strength of the heart muscle responsible for pumping blood to the whole body (deconditioning).¹ However, more research and tools are needed to identify the exact causes of POTS. Additionally, POTS may be triggered following viral or bacterial infection, physical trauma, surgery, or pregnancy — of which infection is the most commonly reported trigger.^{4, 5, 6}

Diagnosis

Similarly to many other rare diseases, the diagnosis of POTS could be challenging and requires specific clinical and hemodynamic (heart rate and blood pressure) criteria.

The diagnostic hemodynamic criteria for POTS is a heart rate increase of 30 beats per minute (bpm) or more, or over 120 bpm, within the first 10 minutes of standing without the absence of orthostatic hypotension (decrease in blood pressure), associated with postural symptoms such as dizziness, lightheadedness, palpitations, chest discomfort, fatigue, brain fog, etc., occurring for at least three months.¹ Clinical and hemodynamic criteria are essential for the diagnosis of POTS. Apart from the orthostatic symptom criteria POTS patients may also experience other symptoms such as, frequent nausea, vomiting, diarrhea, constipation, bladder dysfunction, chronic pain, headaches and sleep disturbances.¹ Symptoms may worsen in warm environments, during extensive exercise, during infections, menstrual periods and after exercise.¹

The diagnosis approach of POTS includes several steps: (1) assessment of a complete medical history; (2) a physical exam; (3) essential blood work; and (4), in some cases, special cardiac and neurological testing.¹ For example, using continuous blood pressure and heart rate monitoring, the Tilt Table Test (TTT) can document hemodynamic changes that occur in the body when the patient changes position under a controlled environment. If TTT is unavailable, POTS can be diagnosed with bedside heart rate and blood pressure measurements taken in the lying down and standing up position at 1, 3, 5, 8 and 10-minute intervals.¹

Additionally, POTS can present along with other associated conditions, such as Ehlers-Danlos Syndrome, Celiac disease; Systemic Lupus Erythematosus, Multiple Sclerosis and Autoimmune disorders. In this case, the presentation is classified as “POTS plus”. ^{1, 7} Typically, the diagnosis of the associated condition comes before the diagnosis of POTS.¹

Other forms of orthostatic intolerance can mimic symptoms of POTS; however, they do not meet the hemodynamic criteria for POTS.¹ This includes vasovagal presyncope/syncope, Inappropriate Sinus Tachycardia and Neurogenic Orthostatic Hypotension. Moreover, other medical conditions, such as severe anemia, nutritional deficiencies, endocrinological disorders, medication side effects, excessive use of caffeine, and excessive bed rest, can present with POTS symptoms.¹

Treatment and prognosis

POTS treatment encompasses lifestyle interventions and prescribed medicines. Lifestyle interventions are the first line of therapy, including increased hydration and dietary interventions to increase blood volume, tailored exercises and compression clothing.^{1, 8} Prescribed medicines aim to treat the symptoms of POTS, but there is no POTS-specific approved medication in Canada.¹ Midodrine, Fludrocortisone, Propranolol and Ivabradine are common pharmacological interventions for POTS.¹ Finally, medications and substances that exacerbate or mimic POTS symptoms must be stopped.¹ The goal of the treatment of POTS is to reduce symptoms and improve quality of life and activity tolerance.

POTS Support Groups and Resources:

Dysautonomia International, a patient advocacy organization, has an interactive map where one can find support groups and healthcare providers based on the regions and offer online education for patients and families.

Acknowledgements:

This article was written in partnership with Dr. Juan Camilo Guzman, M.D. MSc, FRCPC, who specializes in POTS and is the director of the Syncope and Autonomic Disorders Unit at Hamilton General Hospital.

References:

Raj, S. R., Guzman, J. C., Harvey, P., Richer, L., Schondorf, R., Seifer, C., ... & Sheldon, R. S. Canadian Cardiovascular Society position statement on postural orthostatic tachycardia syndrome (POTS) and related disorders of chronic orthostatic intolerance. Canadian Journal of Cardiology. https://pubmed.ncbi.nlm.nih.gov/32145864/ Published March 2020.
Raj, S. R., Fedorowski, A., & Sheldon, R. S. (2022). Diagnosis and management of postural orthostatic tachycardia syndrome. Cmaj. https://www.cmaj.ca/content/194/10/E378 Published March 14, 2022.
Olshansky, B., Cannom, D., Fedorowski, A., Stewart, J., Gibbons, C., Sutton, R., ... & Benditt, D. G. (2020). Postural orthostatic tachycardia syndrome (POTS): a critical assessment. Progress in cardiovascular diseases. https://pubmed.ncbi.nlm.nih.gov/32222376/ Published March 25, 2020.
Thieben, M. J., Sandroni, P., Sletten, D. M., Benrud-Larson, L. M., Fealey, R. D., Vernino, S., ... & Shen, W. K. (2007, March). Postural orthostatic tachycardia syndrome: the Mayo Clinic experience. Mayo Clinic Proceedings.https://pubmed.ncbi.nlm.nih.gov/17352367/ Published March 2007.
Blitshteyn, S., & Whitelaw, S. (2021). Postural orthostatic tachycardia syndrome (POTS) and other autonomic disorders after COVID-19 infection: a case series of 20 patients. Immunologic research. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8009458/ Published March 30, 2021.
Kanjwal, K., Jamal, S., Kichloo, A., & Grubb, B. P. (2020). New-onset postural orthostatic tachycardia syndrome following coronavirus disease 2019 infection. The Journal of Innovations in Cardiac Rhythm Management. https://pubmed.ncbi.nlm.nih.gov/33262898/ Published November 15, 2020.
Mannan, H., & Pain, C. M. (2023). Sex adjusted standardized prevalence ratios for celiac disease and other autoimmune diseases in patients with postural orthostatic tachycardia syndrome (POTS): A systematic review and meta-analysis. Heliyon. https://pubmed.ncbi.nlm.nih.gov/36816268/ Published Jan 14, 2023
Fu, Q., VanGundy, T. B., Galbreath, M. M., Shibata, S., Jain, M., Hastings, J. L., ... & Levine, B. D. (2010). Cardiac origins of the postural orthostatic tachycardia syndrome. Journal of the American College of Cardiology. https://pubmed.ncbi.nlm.nih.gov/20579544/ Published Jun 22, 2012.