What is paroxysmal supraventricular tachycardia?
Episodes of faster-than-normal heart rate characterize paroxysmal supraventricular tachycardia (PSVT). PSVT is a fairly common type of abnormal heart rate. It can occur at any age and in people who don’t have other heart conditions.
The heart’s sinus node typically sends electrical signals to tell the heart muscle when to contract. In PSVT, an abnormal electrical pathway causes the heart to beat faster than normal. Episodes of rapid heart rate can last from a few minutes to several hours. A person with PSVT can have a heart rate as high as 250 beats per minute (bpm). A normal rate is between 60 and 100 bpm.
PSVT can cause uncomfortable symptoms, but it’s not usually life-threatening. Most people don’t need long-term treatment for PSVT. There are medications and procedures that may be necessary in some cases, especially where PSVT interferes with heart function.
The term “paroxysmal” means that it only happens from time to time.
PSVT affects about 1 in every 2,500 children. It is the most frequent abnormal heart rhythm in newborns and infants. Wolff-Parkinson-White syndrome (WPW) is the most common type of PSVT in children and infants.
PSVT is more common in adults under age 65. Adults over age 65 are more likely to have atrial fibrillation (AFib).
In a normal heart, the sinus node directs electrical signals through a specific pathway. This regulates the frequency of your heartbeats. An extra pathway, often present in supraventricular tachycardia, can lead to the abnormally fast heartbeat of PSVT.
There are certain medications that make PSVT more likely. For example, when taken in large doses, the heart medication digitalis (digoxin) can lead to episodes of PSVT. The following actions can also increase your risk of having an episode of PSVT:
- ingesting caffeine
- ingesting alcohol
- using illegal drugs
- taking certain allergy and cough medications
The symptoms of PSVT resemble the symptoms of an anxiety attack and can include:
- heart palpitations
- a rapid pulse
- a feeling of tightness or pain in the chest
- shortness of breath
In more serious cases, PSVT can cause dizziness and even fainting due to poor blood flow to the brain.
Sometimes, a person experiencing symptoms of PSVT may confuse the condition with a heart attack. This is especially true if it’s their first PSVT episode. If your chest pain is severe you should always go to the emergency room for testing.
If you have an episode of fast heartbeats during an examination, your doctor will be able to measure your heart rate. If it’s very high, they may suspect PSVT.
To diagnose PSVT, your doctor will order an electrocardiogram (EKG). This is an electrical tracing of the heart. It can help determine which type of rhythm problem is causing your fast heart rate. PSVT is only one of many causes of abnormally fast heartbeats. Your doctor will also likely order an echocardiogram, or ultrasound of the heart, to evaluate the size, movement, and structure of your heart.
If you have an abnormal heart rhythm or rate, your doctor may refer you to a specialist who is an expert in electrical problems of the heart. They are known as electrophysiologists or EP cardiologists. They may perform an electrophysiology study (EPS). This will involve threading wires through a vein in your groin and up into your heart. This will allow your doctor to evaluate your heart’s rhythm by checking the electrical pathways of your heart.
Your doctor may also monitor your heart rate over a period of time. In this case, you may wear a Holter monitor for 24 hours or longer. During that time, you’ll have sensors attached to your chest and will wear a small device that records your heart rate. Your doctor will assess the recordings to determine if you have PSVT or some other type of abnormal rhythm.
You might not need treatment if your symptoms are minimal or if you only have episodes of rapid heart rate occasionally. Treatment may be necessary if you have an underlying condition causing the PSVT or more severe symptoms like heart failure or passing out.
If you have a rapid heart rate but your symptoms aren’t severe, your doctor can show you techniques to return your heart rate to normal. It’s called the Valsalva maneuver. It involves closing your mouth and pinching your nose while trying to exhale and straining as if you were trying to have a bowel movement. You should do this while sitting and bending your body forward.
You can perform this maneuver at home. It may work up to 50 percent of the time. You can also try coughing while sitting and bending forward. Splashing ice water on your face is another technique to help lower your heart rate.
Treatments for PSVT include medications, such as or flecainide or propafenone, to help regulate your heartbeat. A procedure called radiofrequency catheter ablation is a common way to correct PSVT permanently. It’s performed in the same way as an EPS. It allows your doctor to use electrodes to disable the electrical pathway that’s causing the PSVT.
If your PSVT doesn’t respond to other treatments, your doctor may surgically implant a pacemaker into your chest to regulate your heart rate.
PSVT is not life-threatening. However, if you have an underlying heart condition, PSVT could increase your risk of congestive heart failure, angina, or other abnormal rhythms. Remember that your outlook depends on your overall health and available treatment options.