• Postural   -   Position of the Body

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• Tachycardia   -   Fast Heart Rate

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• Syndrome   -   A Combination of Symptoms

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Postural tachycardia syndrome is an abnormality of the functioning of the autonomic (involuntary) nervous system. 

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Definition and Diagnostic Criteria:

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• Patient must experience PoTS symptoms mostly when upright over a period of at least 3 months.

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• A sustained increase in heart rate of greater than 30 beats per minute within 10 minutes of standing.

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• Those aged 12-19 years require an increase of at least 40 beats per minute.

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• These criteria may not apply to those with a low heart rate when resting.

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• There is usually no drop in blood pressure on standing.

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• Many symptoms are experienced in the upright position (usually standing) and relieved by lying down. 

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The Autonomic Nervous System

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Postural Tachycardia Syndrome (PoTS) is an abnormality of the autonomic nervous system (ANS). A malfunctioning ANS is sometimes called ‘dysautonomia’. The autonomic nervous system is in charge of all bodily functions that we don’t have to think about, such as:

 

• Heart rate and blood pressure regulation

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• Digestion

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• Bladder control

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• Sweating

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• Stress response

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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.

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What should Happen to my Blood when I Stand up?

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When a healthy person stands up, blood vessels narrow, and heart rate increases slightly to maintain blood supply to heart and brain.

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What Happens when I have PoTS and Stand up?

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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. 

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In some cases, PoTS has been reported to have developed after: 

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• An infection such as a viral or bacterial illness.

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• A life stressor such as pregnancy or surgery.

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• A traumatic event.

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• Immunisation.

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However, a link with these potential triggers remains unclear.

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Credit: PoTS UK - Click Here