POTS is defined as a sustained heart rate increase of >30 beats/minute within 10 min of standing or head-up tilt in the absence of orthostatic hypotension (meaning the blood pressure does not drop by more than 20/10 mmHg).
For patients 12-19 years old, the heart rate must increase by at least 40 beats/minute.
This may be accompanied by symptoms that are relieved by lying down.
Who is Affected?
POTS affects an estimated 500,000 Americans. It is a disorder that more frequently affects young women (with approximately 4 female cases for each male case), often less than 35 years of age.
These patients experience an excessive heart rate increase when they stand. This heart rate increase is a sign that the cardiovascular system is working hard to maintain blood pressure and blood flow to the brain in the presence of a disordered cardiovascular regulation.
Causes:
The cause of POTS is unknown. For many years, such patients were felt to have deconditioning and were encouraged to pursue a more vigorous exercise regimen. However, it is clear that many individuals with these symptoms have a more serious problem than mere deconditioning. The onset is often predated by a recent viral infection.
Patients can undergo extensive without identifying a specific cause of the symptoms, and therefore most patients remained undiagnosed. These difficulties are compounded by fluctuations in severity of tachycardia and symptoms and a lack of official diagnosis codes for POTS. Another problem in the diagnosis of POTS is its overlap with other conditions such as:
- Chronic Fatigue Syndrome (CFS)
- Neurally Mediated Syncope (NMS)
- Physical deconditioning
Signs & Symptoms:
The following signs and symptoms may indicate POTS if you have been experiencing them for six months or more:
- 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 ("brain fog")
- Tiredness
- Weakness
- Occasional fainting
- Nausea
- Chest discomfort
- Shortness of breath
- Similar orthostatic symptoms of inadequate cerebral perfusion can occur transiently after serious debilitating illness, substantial weight loss and deconditioning or spaceflight
Other symptoms that have been reported in patients with POTS include:
- Abdominal discomfort and bloating
- Constipation
- Diarrhea
- Changes in sweating
- Sleep problems
- Sense of anxiety