Postural Orthostatic Tachycardia Syndrome

The following information is available at https://www.potsuk.org.

Postural position of the body

Tachycardia increased heart rate

Syndrome a combination of symptoms

What is POTs?

The Postural Tachycardia Syndrome (PoTS) is an abnormality of the autonomic nervous system (sometimes called ‘dysautonomia). The autonomic nervous system (ANS) is in charge of all bodily functions that we dont have to think about, such as:

- Heart rate and blood pressure regulation
- Digestion
- Bladder control
- Sweating
- Stress response

The sympathetic nervous system is part of the autonomic nervous system. It produces the ‘fight or flight or ‘stress response. When activated, a chemical called norepinephrine is released. Amongst other things, this causes an increase in heart rate and blood pressure.

When a healthy person stands up, blood vessels contract and heart rate increases slightly to maintain blood supply to heart and brain. In PoTS, this automatic adjustment to upright posture is not working correctly, resulting in an excessive rise in heart rate, increased norepinephrine in the blood and altered blood flow to the brain.

Diagnosis

To be diagnosed with PoTS, an individual must experience a group of symptoms in the upright position (usually standing) that are relieved by lying down. A persistent increase in heart rate of 30 beats per minute (40 bpm if under 19 years of age) should be recorded within ten minutes of standing. Blood pressure (BP) does not always drop in PoTS.

A common test for POTs is the Tilt Table Test. This involves lying on a table that can be tilted to an angle of 60 to 70 degrees in a quiet, dimly lit, temperature controlled room. Blood pressure and heart rate are recorded in a continuous manner. After a period of 5 to 20 minutes of lying flat, the table is tilted. Although a diagnosis of PoTS should be made by an increase in heart rate of 30 bpm within the first 10 minutes, this upright position can last between 10 and 45 minutes. The patient will be asked how they are feeling during the test, so symptoms can be matched with heart rate and blood pressure. The test will end if your blood pressure becomes too low, satisfactory results have been obtained, or the maximum time has elapsed.

Symptoms

Symptoms can be debilitating, ranging from mild to severe and varying from day to day.

- Dizziness or light-headedness or presyncope (almost fainting)
- Syncope (fainting or blackouts): Approximately 30 % of people with PoTS experience fainting.
- Palpitations
- Headaches
- Tiredness or weakness
- Brain fog
- Shakiness or Tremulousness
- Shortness of breath
- Chest pain
- Excessive or patchy reduced sweating
- Gut problems
- Poor sleep
- Visual problems
- Bladder problems

Triggers which may worsen symptoms

- Excess heat
- After eating – especially refined carbohydrate eg sugar, white flour
- Speed of positional change – dont stand up quickly
- Dehydration
- Time of day (may be worse in the morning, especially rising after wakening)
- Menstrual period
- Deconditioning or prolonged bed rest
- Alcohol which dilates blood vessels
- Exercise (occasional exercise can cause one to feel worse, but an ongoing exercise program can improve symptoms)

Some conditions related to POTs

- Chronic Fatigue Syndrome
- Joint hypermobility syndrome / hypermobile Ehlers Danlos Syndrome
- Mast Cell Activation Disorder

Patients can be very disabled by their symptoms. Fortunately, for many patients, symptoms will improve with a combination of life style changes and medication. However some will have problems over many years.