Postural Tachycardia Syndrome (PoTS)
Postural Tachycardia Syndrome is also called Postural Orthostatic Tachycardia Syndrome or PoTS. It is an abnormal response by the autonomic nervous system to upright posture. When humans stand up, there should be minimal change in their blood pressure and heart rate. In PoTS, it is thought that blood vessels fail to narrow to maintain blood pressure. Blood descends with gravity into the abdominal cavity and limbs. The heart races and, in some people, noradrenaline levels increase in an attempt to compensate. Symptoms result from reduced blood flow within the brain and increased blood levels of noradrenaline.
Definition and Symptoms
PoTS is defined as a sustained increase in heart rate of 30 or more beats per minute within 10 minutes of moving from a lying to standing position (40 beats per minute for those age 12-19 years). Heart rate often increases to more than 120 beats per minute and blood pressure does not usually drop. There must also be symptoms of orthostatic intolerance (symptoms provoked by standing and relieved by lying down).
- Cardiovascular - light-headedness, syncope (fainting), palpitations, breathlessness, chest pains, puffiness and purplish discolouration of feet and hands.
- Gastrointestinal - nausea, diarrhoea, abdominal pain, bloating.
- General -Tiredness, weakness, headache, tremors, sleep disturbances, difficulty exercising.
Symptoms tend to be worse on standing or prolonged sitting and improve upon lying flat. They are worsened by heat, alcohol, exercise, large meals and lack of fluids.
Disability has been shown to be similar to that found in chronic obstructive airways disease and heart failure.
PoTS may be provoked by viral infection, pregnancy, immunisation and traumatic events. The ‘developmental’ form of PoTS is usually of gradual onset in teenagers. In ‘Hyperadrenergic’ PoTS, patients may have very high noradrenaline levels and experience a sense of anxiety, tremor and cold sweaty hands and feet.
PoTS is associated with the following illnesses:
Joint Hypermobility Syndrome, Chronic Fatigue Syndrome, Diabetes, SLE, Amyloidosis, Sarcoidosis, Cancer, Alcoholism and poisons such a lead and chemotherapy.
Diagnosis is usually made by Tilt Table Test or Stand Test. There should be a sustained increase in heart rate of 30 beats per minutes within the first 10 minutes of upright tilt or active standing. Blood pressure usually remains stable or increases slightly, although some patients will also experience a drop in blood pressure
As there is limited awareness of PoTS within the medical communities, it can be mistaken for other conditions including vaso-vagal syncope, chronic fatigue syndrome, anxiety, panic attacks or depression. Symptoms are similar to those found in pheochromocytoma (noradrenaline secreting tumour) and hyperthyroidism and it may be necessary to exclude these conditions.
- Physiological: High fluid (and sometimes salt) intake, support tights, graded exercise programme.
- Medical: A number of drugs are used to treat symptoms; all are unlicensed for this use. They include fludrocortisone, desmopressin, midodrine, beta blockers, ivabradine, SSRIs and SNRIs, pyridostigmine and octreotide.
- Psychological: CBT can help patients come to terms with their illness and disability. Although antidepressants (SSRIs and SNRIs) can be used in PoTS to improve heart rate and blood pressure control, they may also be necessary for co-existing depression.
STARS (Syncope Trust): Syncope Trust And Reflex anoxic Seizures (STARS)
Because of the wide range of symptoms and spectrum of disability and needs, it may often be necessary to obtain further evidence, in the form of a GP or hospital consultant report.
Care and Mobility
While some people with PoTS have minimal symptoms with little impact on their daily activities, others may become wheelchair users or bed-bound. Many patients can live independent lives, but some require constant supervision and assistance with many aspects of daily living. Symptoms can fluctuate significantly and people with PoTS can have good and bad days.
- Fluid intake should be at least 2-3 litres per day. Frequent toilet breaks may be necessary.
- Food intake should preferably be in the form of small frequent meals, low in refined carbohydrates.
- Posture should be monitored. Prolonged standing should be avoided where possible. If patients experience problems with prolonged sitting, elevation of legs with a footstool can be helpful.
- Fatigue is a common symptom and short frequent breaks during activities may be helpful. At times, concentration and stamina may be reduced. Periods of rest throughout the day may be required after only a modest amount of physical activity.
- Mental clouding (‘brain fog’) can significantly impair concentration, especially when people with PoTS are upright ie standing or prolonged sitting.
- Recurrent fainting occurs in 40% of patients and injuries can occur. Certain activities such as bathing, using stairs, etc may need to be supervised.
- Family members may also have PoTS as some forms are inherited. Therefore affected people may also be carers for affected relatives.
Employees with PoTS may require a cool environment and a fan or air conditioning may be necessary. Prolonged standing and sitting should be avoided. They may have special dietary requirements. If fainting is a problem, work colleagues/ first aiders should be instructed in how to manage an unconscious person.
It may be necessary to adapt the home or workplace for use of a wheelchair.
Prognosis and duration
Many people will improve with time, especially those with the developmental and post-viral forms of PoTS. Those with the auto-immune or inherited types are likely to be affected for life.
Although 25% of people with PoTS are unable to work or attend education, 80-90% will improve with treatment and 60% will return to previous levels of functioning.
Professor Julia L Newton,
Professor of Ageing and Medicine and Associate Dean,
Dr Lesley Kavi