Supraventricular tachycardia - Treating supraventricular tachycardia (SVT)

In many cases, symptoms of supraventricular tachycardia (SVT) stop quickly and no treatment is needed.

However, treatment is available to stop an episode of SVT and prevent future episodes if necessary.

Read on to learn about the different treatments you may be offered. You can also see a summary of the pros and cons of these treatments, which allows you to easily compare your options.

Stopping an SVT episode

If possible, medication and surgery will not be used as the first treatment for ongoing episodes of supraventricular tachycardia. Instead, a technique called vagal manoeuvres may be attempted first.

Vagal manoeuvres

Vagal manoeuvres are techniques designed to stimulate the vagus nerve. Stimulating this nerve can help reduce the speed of the electrical impulses in your heart and stop episodes of supraventricular tachycardia. However, these techniques work in less than 1 in 3 cases.

One of the main vagal manoeuvres used is called the Valsalva manoeuvre. There is no standard way to perform this manoeuvre, but it often involves holding your nose, closing your mouth and trying to exhale hard while straining as if you were on the toilet. If you are in hospital, you may be asked to blow hard into a tube instead.

You can perform a simple version of the Valsalva manoeuvre at home to try to stop an episode of SVT. You can also try dipping your face into a bowl of cold water, as this can have a similar effect.

An alternative vagal manoeuvre is a carotid sinus massage. This involves massaging an area of your neck called the carotid sinus in an attempt to stimulate the vagus nerve. However, this should only be carried out by a health professional and should not be attempted at home. For more information, read the NHS leaflet on carotid sinus massage.

Medication

If vagal manoeuvres are unsuccessful, you may require an injection of a medication called adenosine in hospital. This medication blocks the abnormal electrical impulses in your heart.

Side effects of adenosine are relatively common, but usually short-lived. After an injection you may experience nausea (feeling sick), dizziness, chest tightness or shortness of breath.

An injection of a medication called verapamil may sometimes be used instead of adenosine, but only usually if adenosine is unsuitable (for example, if you have asthma). This is because there is a risk of more serious side effects including low blood pressure.

Cardioversion

If a prolonged episode of supraventricular tachycardia doesn't respond to vagal manoeuvres or medication, or if these treatments are unsuitable, a treatment called cardioversion may be used.

Cardioversion is a relatively simple procedure that uses a machine called a defibrillator to apply an electrical current to your chest. This shocks the heart back into a normal rhythm.

It's usually carried out under general anaesthetic and you should be able to go home the same day.

Cardioversion is a very effective procedure and serious complications are uncommon. However, your chest muscles may feel sore afterwards and areas of skin where the electrical shocks were applied may be red and irritated for a few days.

Preventing future episodes

There are also some treatments that reduce your chances of having further SVT episodes.

Self help

Some supraventricular tachycardia episodes are triggered by things like tiredness, drinking lots of alcohol or caffeine, or smoking lots of cigarettes.

Cutting down on the amount of caffeine or alcohol you drink, stopping or limiting how many cigarettes you smoke, and making sure you get enough rest can help reduce your chances of having further episodes.

Read more about stopping smoking and tiredness and fatigue.

Medication

If necessary, medication can be prescribed to prevent further episodes of SVT by slowing down the electrical impulses in your heart. These medications are taken as a daily tablet and include digoxin, verapamil and beta blockers.

Common side effects of these medications can include dizziness, diarrhoea and blurred vision. Tiredness can occur with beta blockers and men may experience problems getting erections. Less common side effects include difficulty getting to sleep (insomnia) and depression.

If the medication you're prescribed doesn't work or has unpleasant side effects, a more suitable alternative can often be found.

Catheter ablation

If episodes of SVT occur repeatedly, an operation called catheter ablation is the recommended treatment option. This prevents further episodes of SVT by destroying the tiny parts of the heart causing the problems in the heart's electrical system. This is a safe and highly effective treatment and means you no longer need to take medication.

During the procedure, a thin wire called a catheter is inserted into a vein in your upper leg or groin, before being guided to your heart. When the wire reaches the heart, it records the electrical activity to pinpoint the precise location of the problem.

When the problem area is found, high-frequency radiowaves are transmitted to the catheter tip to destroy it, producing a small scar.

You will remain awake during this procedure, but will be given a sedative to relax you. Local anaesthetic is used to numb the area where the catheter is inserted. 

The procedure normally lasts about an hour and a half and you can normally go home the same day you have the procedure. However, sometimes you may need to stay in hospital overnight, for example, if you are operated on in the late afternoon.

Catheter ablation is very effective at preventing future episodes of SVT (19 out of every 20 people treated will never have the problem again), but like all operations it carries a risk of complications. These include bruising and bleeding where the catheter was inserted. Typically any bruising will be small, but even if the bruise is large it will require no treatment and will disappear within two weeks.

There is also a small risk (less than 1 in 100) of the heart's normal electrical system being damaged (heart block). If this happens, you may need a permanent pacemaker to control your heart rhythm.

You should discuss potential benefits and risks of catheter ablation with your surgeon, called an electrophysiologist, before the procedure.