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Supra ventricular tachycardia (SVT)

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You are reading this article because you have attended the Emergency Department with a condition called supra ventricular tachycardia (SVT).

You may have attacks like this again. These techniques aim to help stop your SVT episode when it comes on.

  • The valsalva manoeuvre. Take a deep breath, shut your mouth tight, hold your nose tightly and blow out as hard as you can.
  • The cold water technique. Fill a bowl with cold water and put some ice in it, hold your breath and put your face in the water for a few seconds.

If the attack lasts more than 20 minutes or you feel unwell, you should return to the Emergency Department.

You should cut down on caffeine containing and alcoholic drinks as these can start an attack. Reducing smoking and ensuring you get enough rest may also help.

The doctor who saw you may have arranged for you to see a heart specialist as an outpatient. If you do not receive an appointment within eight weeks you should contact your General Practitioner.

What is an SVT?

This is a condition where your heart begins to go very fast. It is often caused by an extra piece of electrical tissue in your heart that you have had since birth. As a result the electrics of the heart bypass the normal route and lead to a fast heart rate and hence your symptoms.

You might

  • Have palpitations.
  • Feel light headed or nauseous o Have a pain in your chest.
  • Feel short of breath.

This does not mean that you have had a heart attack or that you have angina.

Episodes can last for seconds, minutes, hours or (in rare cases) days. They may occur regularly & frequently (e.g. daily), or very infrequently (e.g. once or twice a year).

Episodes of SVT often happen for no obvious reason but sometimes there is an underlying cause including the use of alcohol and stimulants (including caffeine) and abnormal thyroid function.

While in hospital.

  • SVT is rarely life-threatening. But you may need treatment in hospital if you keep having long episodes. • You will be kept on a heart monitor during your hospital stay.
  • Initially, we will try to use manoeuvres to return you to your normal rhythm. These include blowing into a syringe or tubing whilst we lower your legs and lift your head.
  • If unsuccessful, we may then need to use a medication such as adenosine to try and return the heart to its normal rhythm. Adenosine acts for only a few seconds but it can make you feel strange and may cause some chest discomfort while it is working. Sometimes we have to give more than one dose to return the heart to normal.
  • Once your heart has returned to normal, we will watch you for a short period and then send you home.
  • SVT can recur and therefore we normally ask for your general practitioner to refer you to see a cardiologist to decide if you need any further management.

Future treatment.

  • There are a number of treatments that can be offered to you to stop these attacks happening again. The treatment that you are offered will depend on the type of SVT that you have and your personal preference.
  • Medication. It may be possible to control the attacks by taking medication.
  • Catheter ablation treatment. This may be an option for some types of SVT. This is where a small wire is passed via a large vein in the top of your leg into your heart. The tip of the catheter can destroy a tiny section of heart tissue that causes the abnormal electrical impulses. It can be very successful, and after the procedure you will not need to take medication to prevent SVT.
  • Do nothing. If you have attacks rarely and they do not seem to cause any problems, it may be appropriate to do nothing.
  • Sometimes there is an underlying cause for the SVT. This can include the use of alcohol and stimulants (including caffeine) and abnormal thyroid function. Cutting down on caffeine, alcohol and smoking and ensuring you get enough rest may help reduce the chance of another episode.

General support.

For general medical advice please use the NHS website, the NHS 111 service, walk-in-centres, or your GP.

The NHS website provides online health information and guidance

NHS 111 phone line offers medical help and advice from trained advisers supported by nurses and paramedics. Available 24 hours a day. Calls are free from landlines and mobile phones.

There are walk-in and urgent treatment services at Brighton Station, in Crawley and at Lewes Victoria Hospital.

Patient Advice and Liaison Service (PALS) can be contacted with your comments and concerns, and to provide general support.


RSCH, telephone 01273 664683.

PRH, telephone 01444 448678.

PALS, Royal Sussex County Hospital, Eastern Road, Brighton BN2 5BE.


This information is for guidance purposes only and is in no way intended to replace professional clinical advice by a qualified practitioner.

This article is intended for patients receiving care in Brighton & Hove or Haywards Heath.

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