Postural Orthostatic Tachycardia Syndrome (POTS)
The heart muscle is responsible for circulating blood throughout the body. When the heart does not operate as it is supposed to, blood may not pump normally throughout the body. Postural orthostatic tachycardia syndrome (POTS) is one of a group of conditions characterized by an orthostatic intolerance (OI). OI occurs when a patient has symptoms of low blood volume when they are standing, which are relieved when they lie down.
POTS is distinguished from other OI syndromes by a rapid increase in the heartbeat of more than 30 beats per minute, or a heart rate that exceeds 120 beats per minute within 10 minutes of standing.
There are two main forms of POTS:
- Partial dysautonomic - Patients appear to have mild damage to nerves that affect involuntary bodily function (peripheral autonomic neuropathy), such as the heartbeat. This damage affects the peripheral blood vessels and their ability to maintain normal blood pressure when there is more stress from gravity, such as when the patient stands up. This can cause the blood to pool in the lower areas of the body
- Hyperadrenergic - a less common type of POTS that appears more gradually and to have a genetic component
POTS can also be the result of another condition. When this occurs it is known as secondary POTS. The most common cause of secondary POTS is chronic diabetes mellitus.
The main distinguishing symptoms of POTS are:
- A rapid increase in the heartbeat of more than 30 beats per minute
- A heart rate that exceeds 120 beats per minute, within 10 minutes of standing.
Other symptoms of POTS are similar to those of other OI syndromes, which include experiencing the following upon standing:
Patients with hyperadrenergic POTS may experience the following symptoms while standing:
- A significant tremor
- Cold, sweaty extremities
- A migraine
- Increased urination
Causes and Risk Factors
POTS can affect patients of all genders and age groups. However, women between the ages of 15 and 50 are most commonly diagnosed. Some women experience an increase in POTS symptoms right before their menstrual periods. POTS often begins after a pregnancy, major surgery, trauma or a viral illness.
Patients with peripheral nerve damage or a family history of POTS may be at an increased risk of developing the condition.
Patients with conditions or medical histories associated with secondary POTS may also be at an increased risk. These include:
Diagnosis of POTS will generally begin with the physician taking a medical history and performing a physical exam. During the physical exam, the physician may perform a tilt table study to evaluate the heart and blood pressure when the body changes positions. Based on the tilt table test and the patient's symptoms, an accurate diagnosis can often be made.
In some instances, the physician may order additional tests to rule out other conditions. These diagnostic tests may examine the heart muscle, the blood flow through the heart, and any potential abnormal electrical impulses. An electrocardiogram (EKG) is a painless procedure that provides a picture of the electrical activity of the heart and how the heart is working.
Another diagnostic tool that could be used is an echocardiogram. This noninvasive procedure uses a machine called a transducer that transmits sound waves and bounces them off the heart and back into the transducer. These echoes are then translated into visual images.
Electrophysiology studies may also be used to look at the electrical system of the heart.
Treatment of POTS will vary for each patient, depending on the type, severity and cause of the condition. In some cases, when POTS is caused by an underlying condition such as diabetes, treatment may focus on managing that underlying condition. Other treatment options include physical therapy, lifestyle changes and medication.
For many patients, physical therapy is the best treatment option. Working with a physical therapist and doing exercises at home as part of a gradual reconditioning program will allow the patient to retrain their body to function more efficiently. Gentle resistance training can work to strengthen the skeletal muscle pump, which helps the heart to circulate blood throughout the body. Compression stockings may also be helpful to some patients.
When physical therapy and lifestyle changes are unable to provide adequate symptom relief, medication may be needed. Medication is used to stabilize the patient so that they may begin a reconditioning program, rather than being used as a long-term treatment.
The knowledgeable and highly trained staff at the Cedars-Sinai Heart Institute will work with each patient to determine the best treatment option.