Postural orthostatic tachycardia syndrome

Postural orthostatic tachycardia syndrome (POTS) is a condition characterized by an abnormally large increase in heart rate upon sitting up or standing. POTS in adults is characterized by a heart rate increase of 30 beats per minute within ten minutes of standing up, accompanied by other symptoms. to be considered POTS. POTS is a disorder of the autonomic nervous system that can lead to a variety of symptoms, including lightheadedness, brain fog, blurred vision, weakness, fatigue, headaches, heart palpitations, exercise intolerance, nausea, difficulty concentrating, tremulousness (shaking), syncope (fainting), coldness, pain or numbness in the extremities, chest pain, and shortness of breath. In other cases, it develops after a viral infection, surgery, trauma, autoimmune disease, or pregnancy. It has also been shown to emerge in previously healthy patients after contracting COVID-19, in people with long COVID, or possibly in rare cases after COVID-19 vaccination, though causative evidence is limited and further study is needed. POTS is more common among people who got infected with SARS-CoV-2 than among those who got vaccinated against COVID-19. About 30% of severely infected patients with long COVID have POTS. Risk factors include a family history of the condition.

small and frequent meals,
avoidance of immobilization,

Medications used may include:

beta blockers,
pyridostigmine,
midodrine,
fludrocortisone,

More than 50% of patients whose condition was triggered by a viral infection get better within five years.

It is estimated that 1–3 million people in the United States have POTS. The average age for POTS onset is 20, and it occurs about five times more frequently in females than in males.

Individuals living with POTS experience a diminished quality of life compared to healthy individuals, due to disruptions in various domains such as standing, playing sports, symptom anxiety, and impacts on school, work, or spiritual (religious) domains—these disruptions affect their daily life and overall well-being.

In adults, the primary manifestation is an increase in heart rate of more than 30 beats per minute within ten minutes of standing up. The resulting heart rate is typically more than 120 beats per minute.

Up to one-third of POTS patients experience fainting for many reasons, including but not limited to standing, physical exertion, or heat exposure. Some POTS patients may develop blood pooling in the extremities, characterized by a reddish-purple color of the legs and/or hands upon standing. Other POTS patients only exhibit the cardinal symptom of orthostatic tachycardia.

Additional signs and symptoms are varied, and may include excessive sweating, lack of sweating, heat intolerance, digestive issues such as nausea, indigestion, bloating, constipation or diarrhea, post-exertional malaise, coat-hanger pain, brain fog, and syncope or presyncope.

Whereas POTS is primarily characterized by its impact on the autonomic and cardiovascular systems, it can lead to substantial functional impairment. This impairment, often manifesting as symptoms such as fatigue, cognitive dysfunction, and sleep disturbances, can significantly diminish the patient's quality of life.

A potential cause for brain fog is a decrease in cerebral blood flow (CBF), especially in the upright position.

There may be a loss of neurovascular coupling and reduced functional hyperemia in response to cognitive challenge under orthostatic stress, perhaps related to a loss of autoregulatory buffering of beat-by-beat fluctuations in arterial blood flow.

Comorbidities

Conditions that are commonly reported with POTS include:

Migraine headaches (40%)
Irritable bowel syndrome (30%)
Ehlers–Danlos syndrome (18–25%)
Asthma (20%)
Fibromyalgia (20%)
Reynaud's syndrome (16%)
Iron deficiency anemia (16%)
Autoimmune disease (16%)
Gastroparesis (14%)
Vasovagal syncope (13-25%)
Inappropriate sinus tachycardia (11%)
Mast cell activation disorder (9%)

There are some overlaps between POTS and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), with evidence of POTS in 10–20% of ME/CFS cases.

A subset of POTS patients have markedly reduced myocardial MIBG reuptake via MIBG myocardial scintigraphy, interpreted to be a potential manifestation of autonomic cardiac neuropathy, although reduced expression of the norepinephrine transporter may also result in impaired MIBG reuptake and has been implicated in POTS.

In up to 50% of cases, symptom onset followed a viral illness. It has been shown to emerge in previously healthy patients after COVID-19, Possible mechanisms for COVID-induced POTS are hypovolemia, autoimmunity/inflammation from antibody production against autonomic nerve fibers, and direct toxic effects of COVID-19, or secondary sympathetic nervous system stimulation. long COVID, irritable bowel syndrome, anemia, hyperthyroidism, fibromyalgia, diabetes, amyloidosis, sarcoidosis, systemic lupus erythematosus, and cancer. Genetics likely plays a role, with one study finding that one in eight POTS patients reported a history of orthostatic intolerance in their family. It has been proposed that there are parallels between POTS and physical deconditioning or people who have undergone prolonged periods of bed rest.

Autoimmunity

There is an increasing number of studies indicating that POTS is an autoimmune disease. A high number of patients has elevated levels of autoantibodies against the α1-adrenergic receptor and against the muscarinic acetylcholine M4 receptor.

Elevations of autoantibodies targeting the α1-adrenergic receptor have been associated with symptom severity in patients with POTS. Signs of innate immune system activation with elaboration of pro-inflammatory cytokines has also been reported in a cohort of POTS patients.

Secondary POTS

If POTS is caused by another condition, it may be classified as secondary POTS. With MCAS, it is not yet clear whether MCAS is a secondary cause of POTS or simply comorbid; however, treating MCAS for these patients can significantly improve POTS symptoms.

There have also been reports of patients experiencing co-occurring POTS, May–Thurner syndrome, and EDS.

Diagnosis

thumb|Results of a tilt table test positive for POTS

POTS is a complex disorder with a multifactorial etiology, and the diagnosis of POTS is challenging. Patients must show a heart rate increase of at least 30 beats per minute (or over 120 bpm) within 10 minutes of standing, and diagnosis requires symptoms without a major drop in blood pressure. Doctors must also rule out other conditions, such as dehydration or heart disease. The average number of physicians seen before receiving diagnosis is seven, and the average delay before diagnosis is 4.7 years. dehydration, orthostatic hypotension, heart problems, adrenal insufficiency, epilepsy, and Parkinson's disease must not be present.

Alternative tests to the tilt table test are also used, such as the NASA Lean Test and the adapted Autonomic Profile (aAP) which require less equipment to complete. Nonpostural testing, such as the Valsalva maneuver, which may minimize the triggering of POTS symptoms, can be used prior to or in conjunction with the aforementioned techniques as a potential indicator of orthostatic intolerance, including POTS.

Orthostatic intolerance

An increase in heart rate upon moving to an upright posture is known as orthostatic (upright) tachycardia (fast heart rate). It occurs without any coinciding drop in blood pressure, as that would indicate orthostatic hypotension. but not arm. This is believed to reflect peripheral sympathetic denervation in the lower limbs.

Large meals worsen symptoms for some people. These people may benefit from eating small meals frequently throughout the day instead. Excessive consumption of caffeine beverages should be avoided, because they can promote urine production (leading to fluid loss) and consequently hypovolemia. Techniques that increase a person's capacity for exercise, such as endurance training or graded exercise therapy, can relieve symptoms for some patients. Aerobic exercise performed for 20 minutes a day, three times a week, is sometimes recommended for patients who can tolerate it. Exercise may have the immediate effect of worsening tachycardia, especially after a meal or on a hot day.

Medication

If non-pharmacological methods are ineffective, medication may be necessary. or fludrocortisone, among others. However, fludrocortisone may cause hypokalemia (low potassium levels).

While people with POTS typically have normal or even elevated arterial blood pressure, the neuropathic form of POTS is presumed to constitute a selective sympathetic venous denervation. However, this medication may be hampered by poor oral bioavailability. Indirectly acting sympathomimetics, like the norepinephrine releasing agents ephedrine and pseudoephedrine and the norepinephrine–dopamine reuptake inhibitors methylphenidate and bupropion, have also been used in the treatment of POTS.

|Splanchnic–mesenteric vasoconstriction

|Splanchnic vasoconstriction

|Octreotide

| rowspan="2" |Hypovolemic POTS

|Synthetic mineralocorticoid

|Forces the body to retain salt. Increase blood volume

|Fludrocortisone (Florinef)

|Vasopressin receptor agonist

|Helps retain water, increases blood volume

|Desmopressin (DDAVP)

| rowspan="5" |Hyperadrenergic POTS

|Beta-blockers (non-selective)

| rowspan="2" |Decrease sympathetic tone and heart rate.

|Propranolol (Inderal)

|Beta-blockers (selective)

|Metoprolol (Toprol), Bisoprolol

|α2-Adrenergic receptor agonist

|Decreases blood pressure and sympathetic nerve traffic.

|Clonidine,

| rowspan="5" |Other (refractory POTS)

|Psychostimulant

|Improve cognitive symptoms (brain fog)

|Modafinil

|Central nervous system stimulant

|Tighten blood vessels. Increases alertness and improves brain fog.

|Methylphenidate (Ritalin, Concerta)

|Direct and indirect α1-adrenoreceptor agonist.

|Increased blood flow

|Ephedrine and Pseudoephedrine

|Norepinephrine precursor

|Improve blood vessel contraction

|Droxidopa (Northera)

|α2-Adrenergic receptor antagonist

|Increase blood pressure

|Yohimbine

Prognosis

POTS has a favorable prognosis when managed appropriately. a systematic review found that 86% of patients with post-COVID POTS showed symptomatic improvement over time, but many remained symptomatic for several months. Approximately 90% of people with POTS respond to a combination of pharmacological and physical treatments. Outcomes are more guarded for adults newly diagnosed with POTS. Some people do not recover, and a few even worsen with time. One study estimated a minimal rate of 170 POTS cases per 100,000 individuals, but the true prevalence is likely higher due to underdiagnosis. POTS often begins during the teenage years, and symptoms may improve over time for younger patients.

Notable cases

British politician Nicola Blackwood revealed in March 2015 that she had been diagnosed with Ehlers–Danlos syndrome in 2013 and that she had later been diagnosed with POTS. She was appointed Parliamentary Under-Secretary of State for Life Science by Prime Minister Theresa May in 2019 and given a life peerage that enabled her to take a seat in Parliament. As a junior minister, it is her responsibility to answer questions in parliament on the subjects of Health and departmental business. When answering these questions, it is customary for ministers to sit when listening to the question and then to rise to give an answer from the despatch box, thus standing up and sitting down numerous times in quick succession throughout a series of questions. On 17 June 2019, she fainted during one of these questioning sessions after standing up from a sitting position four times in the space of twelve minutes, and it was suggested that her POTS was a factor in her fainting. Asked about the incident, she stated: "I was frustrated and embarrassed my body gave up on me at work ... But I am grateful it gives me a chance to shine a light on a condition many others are also living with."

In 2024, Taiwanese tennis player Latisha Chan revealed that she was diagnosed with POTS back in 2014 and has been receiving treatments before Summer Olympics as well. Her condition was considered career-threatening, but has had her career extended by over a decade due to external counterpulsation.

In her 2024 memoir Just Add Water, Olympic gold medalist swimmer Katie Ledecky shared that she has a mild form of POTS.

Latvian basketball player Kristaps Porziņģis was sidelined for much of the 2024–25 NBA season with POTS.