Supraventricular tachycardia
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What is supraventricular tachycardia?
Supraventricular tаϲhуcаrdiа (“SVT”) is a heartbeat that is faster than normal. ЅVΤ that starts and stops suddenly is called “paroxysmal supraventricular tаϲhуϲаrԁia” (“ΡSVТ”). (Paroxysmal means a sudden attack.)
ЅVΤ happens because of a problem with the heart’s electrical system. The left and right ventricles are the main pumping chambers of the heart. ЅVТ starts above the ventricles.
With SVT, the fast heartbeat can last from seconds to hours. It can happen when you are at rest. But in some people, exercise triggers it.
The 3 main types of SVТ are called:
- Atrioventricular nodal reentry tаϲhуϲаrԁia (“AVNRT”)
- Atrioventricular reentry tаϲhуϲardia (“ΑVRT”)
- Atrial tаϲhуϲаrԁia
What are the symptoms of SVT?
You might not have symptoms. Or you might feel like your heart is beating too fast, beating hard, or seems to skip a beat. These kinds of heartbeat changes are called “palpitations.”
You might also feel:
- Lightheaded
- Dizzy
- Very tired
If you also have coronary heart disease, you might also:
- Have trouble breathing
- Feel a tightness in your chest
Is there a test for SVT?
Yes. Your doctor or nurse will do a test called an electrocardiogram (“ECG”). This test measures the electrical activity in your heart.
Other possible tests include various types of longer-term heart monitoring. This can be done using 1 of several devices:
Holter monitor
This is a small, portable machine that you wear. It records all of your heart's electrical activity over 1 or 2 days.
Event or loop monitor
These are similar to Holter monitors but smaller, because they don't record all of the time. Instead, you start the monitor when you feel symptoms. Your doctor will likely have you wear this type of monitor every day for about a month.
Patch monitor
This is a newer type of monitor. It goes directly on the skin, without wires, and can be worn for up to 30 days. You wear it all of the time while you go about your usual activities.
How is SVT treated?
The treatment depends on the cause of the tаϲhуϲаrdiа.
For some types of heart rhythms, your doctor might suggest ways to slow it down. They might have you cough, or bear down as if you’re having a bowel movement. Doing these things can affect the nerve that helps control your heartbeat.
Other treatments can include:
- Medicines to control your heart rhythm
- Cardioversion – This involves applying an electrical current to the heart to fix its rhythm.
If the tаϲhуϲardia comes back often and causes symptoms, treatment can include:
- Ablation – This is a treatment to destroy the small part of the heart that is sending the abnormal electrical signals. It uses energy such as heat (called "radiofrequency ablation") and cold (called "cryoablation").
- Medicines to prevent the abnormal rhythm
Your doctor might suggest that you limit caffeine.
When should I call for help?
Call for an ambulance (call 9-1-1) if you have:
- Trouble breathing
- Chest pain that lasts for more than a few minutes
Call your doctor or nurse if you pass out or feel very dizzy.
If you do not have these problems, but you often feel your heart beating fast or irregularly, talk to your doctor or nurse.