Supraventricular tachycardia

Supraventricular tachycardia is a condition where the heartbeat is much faster than it should be. Anyone can get it, at any age, and it often shows up for the first time in children or young adults.

In most cases, supraventricular tachycardia is harmless. It doesn't usually last long, and it can settle on its own without treatment.

Some people are born with an abnormality in the heart's natural "wiring", also called its conduction system. This lets a short circuit develop. In certain situations, the short circuit can make the heart race very fast, which is what happens in supraventricular tachycardia.

One example is Wolff-Parkinson-White syndrome. Here there's an abnormal electrical connection between the:

• atria (upper heart chambers), and
• the ventricles (lower heart chambers)

Some people with this condition can develop supraventricular tachycardias because of this short circuit.

If you have supraventricular tachycardia, you'll usually feel your heart racing in your chest or throat. The heart rate is usually between 140 to 180 beats per minute, but it can go as high as 250. A normal heartbeat at rest is 60 to 100 beats per minute.

During an episode of supraventricular tachycardia, the heart muscle contracts very fast. Because of this, it cannot relax properly between contractions to fill with blood, and so less blood is pumped around the body.

For that reason, you may also feel:

• chest pain
• dizziness
• light-headedness
• fatigue (tiredness)
• breathlessness

On rare occasions, you may faint because of a drop in blood pressure.

These symptoms vary in length and frequency.

If your doctor thinks you might have supraventricular tachycardia, you'll be referred for tests. These can include an:

• electrocardiogram (ECG)
• ambulatory heart monitor
• echocardiogram

In people who are at risk of supraventricular tachycardia, an episode can often be set off by one of several common triggers. These include:

• stress
• anxiety
• a change in posture
• some medicines
• alcohol
• caffeine
• smoking
• recreational drugs

Treatment for supraventricular tachycardia is not the same for everyone. What your doctor suggests will depend on:

• the type of supraventricular tachycardia you have
• your symptoms
• treatment of any underlying cause
• your age
• your overall health

Treatment for supraventricular tachycardia focuses on controlling the rate and rhythm of your heart. The options are:

• medicine, such as beta blockers and other anti-arrhythmic drugs
• electric shock treatment (DC cardioversion), used in an urgent case
• radiofrequency ablation