Supraventricular Tachycardia

Supraventricular Tachycardia

Supraventricular tachycardia (SVT) causes episodes of a fast heartbeat. ‘Thumping heart’ sensations (palpitations) and other symptoms may occur during each episode. Regular medication can prevent episodes of SVT. Another treatment option in some cases is to destroy a tiny part of the heart that triggers the SVT.

What is a supraventricular tachycardia?

Tachycardia means a fast heart rate. Supraventricular means coming from above the ventricle.
During an episode of supraventricular tachycardia (SVT), the heartbeat is not controlled by the SA node (the normal timer of the heart). Another part of the heart overrides this timer with faster impulses. The source or trigger of the impulse in an SVT is somewhere above (supra) the ventricles, but the impulse then spreads to the ventricles.

Who develops supraventricular tachycardia?

In most cases, the first episode of SVT begins in childhood or early adulthood. However, a first episode of SVT can occur at any age. It is an uncommon condition, but the exact number of people affected is not known.

Certain triggers may increase the risk of developing an episode of SVT, especially in those people who have already had episodes. These may include:

• Medications. These include some asthma inhalers and some types of herbal supplements and cold remedies.
• Drinking large amounts of caffeine or alcohol.
• Stress or emotional upset.
• Smoking.

Avoiding these triggers will often reduce the frequency of SVTs.

What are the symptoms of a supraventricular tachycardia?

Symptoms last as long as the episode of SVT lasts. This may be seconds, minutes, hours or, rarely, longer.

Possible symptoms include the following:

• Your pulse rate becomes 140-200 beats per minute (bpm). Sometimes your pulse may be even faster (the normal pulse is 60-100 bpm).
• ‘Thumping heart’ sensations (palpitations).
• You may have no symptoms, or you are just aware that your heart is beating fast.
• Sometimes your blood pressure may become low with too fast a heart rate, especially if it continues beating too quickly for several hours. In some cases this causes a faint or collapse. This is more likely if you are older and have other heart or lung problems.

An episode of SVT usually starts very suddenly and for no apparent reason. It may last just a few seconds or minutes; however, it can last several hours. It then stops just as suddenly as it started. Rarely, an episode lasts longer than a few hours.

The time between episodes of SVT can vary greatly. In some cases, short bursts of SVT occur several times a day. At the other extreme, an episode of SVT may occur just once or twice a year. In most cases it is somewhere in between and an episode (paroxysm) of SVT occurs now and again.

If you experience SVT and it causes you to feel dizzy, light headed, breathless or to experience chest pain then you should attend the Emergency Department (A&E).

What are the treatment options for supraventricular tachycardia?

Stopping an episode of SVT

Many episodes of SVT soon stop on their own, and no treatment is then needed. It is sometimes possible to stop an episode of SVT by various measures, including blowing into a 10ml syringe (loosened and blown just hard enough to move plunger), holding your breath or putting your face into cold water. However, if an episode of SVT lasts a long time or is severe, you should attend the Emergency Department (A&E):

• Medicines can be given by injection into a vein which will usually stop an SVT.
• Electric shock treatment to the heart is sometimes used to stop an episode of SVT.

Preventing episodes of SVT

Not treating is an option if episodes of SVT are infrequent, only last a short time, or cause few symptoms. The treatments above have to be balanced against the possible side-effects and risks. Some people prefer to put up with symptoms if they are not too bad and only occur now and then.

You can take medication every day to prevent episodes of SVT. Various medicines can interfere with the electrical impulses in your heart. Examples include verapamil and beta-blockers. If one does not work or causes side-effects, another can often be found to suit you.

Tissue destruction using a catheter (catheter ablation) may be an option for some types of SVT.

Driving

You must inform the DVLA and stop driving if the SVT has caused or might cause any symptoms which incapacitate you when driving (e.g. cause you to faint or severe chest pain). You may be allowed to drive when the cause has been controlled for at least four weeks.

The rules are much stricter if you drive a bus or lorry for work

Patient Experience
We know that being admitted to hospital can be a difficult and unsettling time for you and your loved ones. If you have any questions or concerns, please do speak with a member of staff on the ward or in the relevant department who will do their best to answer your questions and reassure you.

Feedback
Feedback is really important and useful to us – it can tell us where we are working well and where improvements can be made. There are lots of ways you can share your experience with us including completing our Friends and Family Test – cards are available and can be posted on all wards, departments and clinics at our hospitals. We value your comments and feedback and thank you for taking the time to share this with us.

Patient Advice and Liaison Service (PALS)
If you have any concerns or questions about your care, we advise you to talk with the nurse in charge or the department manager in the first instance as they are best placed to answer any questions or resolve concerns quickly. If the relevant member of staff is unable to help resolve your concern, you can contact the PALS Team. We offer informal help, advice or support about any aspect of hospital services & experiences.

Our PALS team will liaise with the various departments in our hospitals on your behalf, if you feel unable to do so, to resolve your problems and where appropriate refer to outside help.

If you are still unhappy you can contact the Complaints Department, who can investigate your concerns. You can make a complaint orally, electronically or in writing and we can advise and guide you through the complaints procedure.

How to contact PALS:
Telephone Patient Services: 0300 123 1732 or via email at: [email protected]
Opening times:
The PALS telephone lines are open Monday to Friday from 8.30am to 4.00pm. Please be aware that you may need to leave a voicemail message, but we aim to return your call within one working day.
If you are unable to understand this leaflet, please communicate with a member of staff.

For additional medical advice, if your symptoms or condition worsens:
Contact your GP
NHS 111: Telephone 111
Get help with your symptoms, NHS111: https://111.nhs.uk/
Information to help you manage your health: www.nhs.uk
In an emergency telephone 999

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