Supraventricular tachycardia

Supraventricular tachycardia

Supraventricular tachycardia is a condition where the heartbeat is abnormally fast.

It can happen to anyone at any age and often occurs for the first time in children or young adults.

In most cases, supraventricular tachycardia is harmless. It doesn’t usually last long and can settle without treatment.

Why it happens

Some people are born with an abnormality of the heart’s natural ‘wiring’ or conduction system. This allows a short circuit to develop. Under certain circumstances, this allows the heart to race very fast.

One example of this is Wolff-Parkinson-White syndrome. This is where 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. This is because of this short circuit.

Symptoms of supraventricular tachycardia

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 can be as high as 250. A normal heartbeat should be 60 to 100 beats per minute at rest.

During a supraventricular tachycardia, the heart muscle contracts very fast. This means that it cannot relax properly between contractions to fill with blood. This reduces the amount of blood being pumped around the body.

Therefore, 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.

Diagnosing supraventricular tachycardia

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

• electrocardiogram (ECG)
• ambulatory heart monitor
• echocardiogram

Causes of supraventricular tachycardia

Common causes of supraventricular tachycardia in people at risk of the condition include:

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

Treating supraventricular tachycardia

The treatment for supraventricular tachycardia varies from person to person. It depends on:

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

Types of treatment

Supraventricular tachycardia treatments focus on controlling the rate and rhythm of the heart. They include:

• medication, like beta blockers and other anti-arrhythmic drugs
• electric shock treatment (DC cardioversion) in an urgent case
• radiofrequency ablation