Postural tachycardia syndrome (PoTS)
Postural tachycardia syndrome (PoTS) is an abnormal increase in heart rate after sitting or standing up. It typically causes dizziness, fainting, sweating and other symptoms.
There are many possible causes of PoTS, but in many cases the condition is unexplained.
It's sometimes known as postural orthostatic tachycardia syndrome.
How does the body normally respond when you sit or stand up?
Normally when you sit or stand up, some of your blood drops under gravity to your belly area, hands and feet.
In response, your blood vessels quickly narrow and your heart rate increases slightly to maintain blood flow to the heart and brain, and prevent blood pressure dropping. This results in a slight increase in blood pressure.
This is all done without needing to think about it by the autonomic nervous system – the nervous system in charge of automatic body functions such as this.
What happens in people with PoTS?
In PoTS, for some reason the autonomic nervous system doesn't function properly. There's a drop in blood supply to the heart and brain when you become upright.
In an attempt to compensate for this, the heart races and the body produces lots of the hormone noradrenaline (one of the hormones that prepares you for "fight or flight").
What are the symptoms of PoTS?
Some people with PoTS just have mild symptoms, but others can be severely affected and find it significantly impacts on their day-to-day life (although the condition is not life threatening).
Typical symptoms are:
- dizziness
- fainting
- headaches
- sweating
- nausea
- poor concentration and memory
- purple hands and feet
- a feeling of anxiety
- chest pains
- bowel problems
- poor sleep
- weakness
- blurred vision
- shaking
- palpitations
- neck or shoulder pain
It's easy to mistake these symptoms for signs of low blood pressure, but blood pressure doesn't necessarily fall in PoTS.
If you think you may have PoTS, see your GP. Some doctors may not be aware of the condition, so it may be helpful to print out this page to take with you to the consultation.
Symptoms can be managed with lifestyle changes and, if necessary, medication.
What's the cause?
In many cases, the cause of this nervous system problem is not known.
Teenagers will sometimes develop PoTS after a growth spurt and find it gradually disappears a few years later.
It can also develop later in life – typically at any age from 15 to 50 – and is much more common in females. It can develop suddenly after a viral illness or traumatic event, or during or after pregnancy.
Some of the other known causes are:
- joint hypermobility syndrome – a condition (often inherited) that results in unusually supple joints and abnormally elastic blood vessels, among other things
- an underlying disease – such as diabetes, amyloidosis, sarcoidosis, lupus, Sjogren's syndrome, multiple sclerosis or cancer (chemotherapy can also sometimes trigger it)
- poisoning – with alcohol or certain metals
- inheriting an abnormal gene, which causes too much of the "fight or flight" hormone noradrenaline to be produced – this inherited form of PoTS is less common
PoTS can be misdiagnosed as chronic fatigue syndrome, anxiety or panic attacks.
How is PoTS diagnosed?
A diagnosis of PoTS is made if your heart rate increases by 30 beats per minute (bpm) or more (40bpm in those aged 12 to 19) after 10 minutes of standing, or if it increases to more than 120 bpm.
By definition, this happens with no drop in blood pressure.
Heart rate is usually measured during the active stand test or the tilt table test.
Tilt table test
This test is carried out in a hospital outpatient department and involves lying flat on a special bed with a footplate.
The bed is tilted upright to about 60-75 degrees for up to 45 minutes and any symptoms are observed.
Some people with PoTS briefly faint when upright, but you'll be in safe hands. Blood pressure and heart rate are recorded continuously.
You may be given medication to take during the test.
Other tests
You may also have any of the following tests:
- an electrocardiogram (ECG) – to rule out other heart problems
- an echocardiogram (heart ultrasound) – to see if the structure of your heart is normal
- the active stand test – where your heart rate and blood pressure are measured after lying down, immediately upon standing, and after 2, 5 and 10 minutes
- 24-hour ambulatory blood pressure and heart rate monitoring – small devices attached to your belt take regular readings while you are doing your normal activities
- 24-hour urine collection – to test urine sodium levels (low sodium may indicate low blood volume)
- blood tests – to test kidney, liver and thyroid function, and measure blood count and calcium and glucose levels
How can it be managed?
You may be able to improve PoTS symptoms by following this advice:
- drink plenty of fluids until your urine is pale yellow – dehydration (a low volume of blood circulating around your body) can worsen PoTS
- keep active, but pace yourself and choose your exercise wisely – swimming, rowing, lower limb resistance training, walking, jogging and pilates can help you keep fit and build muscle (strong calf muscles should help pump blood back to your heart)
- elevate the head end of your bed using a brick or similar, so you're not sleeping flatly horizontal
- try wearing support tights or other forms of compression clothing, to improve blood flow in your legs
- avoid long periods of standing or having your hands over your head
- come up from lying slowly, sitting for a while first – this should reduce your risk of fainting
- avoid long hot baths or showers – the heat can dilate the blood vessels; finish with cool water if possible
- drink a glass of fluid before and after showering
- on a bad day, wash while sitting on a stool by the sink or in the shower, or consider using dry shampoo and wet wipes
Some people with PoTS may need to increase their daily salt intake, but this is not recommended if you have high blood pressure or kidney or heart disease. Your specialist will advise on this.
If you do suddenly feel faint or dizzy, try countering the fall in blood flow by:
- lying down and, if you can, raising your legs – or try crossing your legs, squeezing your thighs together and tightly clenching your buttocks and fists
- drinking one or two glasses of water rapidly – this has been shown to reduce heart rate in people with PoTS
Medication
If a medicine seems to be worsening your PoTS, speak to your GP about switching to an alternative medication, but never come off it without seeking medical advice.
There is currently no medication licensed for the treatment of PoTS, but your specialist might suggest trying a medication "off label", such as:
- a beta-blocker or ivabradine – which decreases the heart rate
- midodrine – which narrows the blood vessels
- fludrocortisone – which decreases the amount of sodium lost in your urine
More information and advice
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