Postural Tachycardia Syndrome (POTS)
What is Postural Tachycardia Syndrome (POTS)?
When a patient’s heart rate speeds up 30 beats per minute or more without much change in blood pressure on standing, the patient may have orthostatic intolerance (OI). Because upright heart rate is usually greatly increased, the more common term used now is Postural Tachycardia Syndrome (POTS). The increase in heart rate may be a sign that the cardiovascular system is working hard to maintain blood pressure and blood flow to the brain.
Symptoms & Signs (for at least 6 months):
- Lightheadedness, palpitations and tremulousness during standing
- Other upright posture symptoms may include:
- Visual changes
- Discomfort in the head and neck
- Throbbing of the head
- Poor concentration
- Occasionally fainting
- Chest discomfort
- Shortness of breath
The Role of Hypovolemia in POTS
Hypovolemia is an abnormal decrease in blood volume, or more specifically an abnormal decrease in the volume of blood plasma. This sometimes occurs in POTS patients. It may occur due to blood pooling in the abdomen and legs.
Long-Term Outlook for Patients with POTS
The majority of patients with POTS have a relatively mild disorder which improves over weeks or months. Most patients will eventually be free of symptoms. However, in some patients, the symptoms are more severe, the duration of the illness may be longer, and the expected recovery may not occur.
Who gets POTS?
POTS is most frequently seen in young women, often less than 35 years of age. Orthostatic intolerance affects an estimated 500,000 Americans and causes a wide range of disabilities.
What causes POTS?
The cause of POTS is unknown. Sometimes, a recent viral infection happens soon before symptoms occur. Many patients remain undiagnosed because the severity changes and the disorder can be called many different names. Another problem in the diagnosis of OI is its overlap with other conditions such as Chronic Fatigue Syndrome (CFS), Neurally Mediated Syncope (NMS), or physical deconditioning.
Patients may also experience hypovolemia, or a decrease in blood plasma volume due to blood pooling in the abdomen and legs.
How is POTS diagnosed?
In addition to asking detailed questions about the patient’s health, the physician will conduct a physical examination, which will include checking blood pressure and heart rate while the patient is lying, sitting, and immediately after standing, as well as after the patient has been upright for two, five, and ten minutes. Sometimes a test called a head upright tilt table will be performed to help confirm the diagnosis.
What is the treatment for POTS?
Treatments for POTS aim to relieve low blood pressure or regulate circulatory problems. These include:
- Orthostatic “exercise”
- Medication therapy, including beta blockers, alpha-2 agonists (such as Clonidine), alpha-1 agonists (such as Midodrine), or Alpha-Methyldopa (Aldomet)
- Drinking water may help to temporarily raise blood pressure
- Salt and /or fludrocortisones
No single treatment has been found to be effective for every patient. Some treatments are more successful than others and are often used together for best results.