Heart Rhythm Clinic
Heart Rhythm Clinic

The Heart Rhythm Clinic deals with general cardiology problems but has a specialist interest in the treatment of patients who suffer with or who are at risk of “cardiac arrhythmias”.

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Heart Rhythm Clinic


Spire Southampton Hospital
Heart Rhythm Clinic
Heart Rhythm Clinic


Treatments & Procedures

What is an arrhythmia?
Sometimes, if the conduction pathway is damaged or becomes blocked; or if an extra pathway exists, the heart's rhythm changes. The heart may beat too quickly (tachycardia), too slowly (bradycardia) or irregularly which may affect the heart's ability to pump blood around the body. These abnormal heartbeats are known as arrhythmias. Arrhythmias can occur in the upper chambers of the heart, the atria or in the lower chambers of the heart, the ventricles.

The type of rhythm disturbance you have is called atrial fibrillation; it is one of the most common types of arrhythmia.  Atrial fibrillation occurs in the atria, in the upper chambers of the heart. In atrial fibrillation, the electrical impulses are not produced by the SA node alone; instead many impulses begin and spread chaotically through the atria. As a result, your heartbeat is usually fast and irregular. The atria are said to be fibrillating when they beat too quickly and irregularly, during this time they are unable to completely empty all of the blood they receive into the ventricles below, this can cause blood to pool and potentially clots to form. Therefore, to prevent you being at an increased risk of stroke your doctor will prescribe you with a blood-thinning drug (anticoagulant) called warfarin. You must continue to take warfarin after the procedure.

In many patients with atrial fibrillation it has been found that the extra electrical signals responsible start in the area around the pulmonary veins on the left side of the heart.

Why do I need a pulmonary vein isolation (PVI) ablation?
Your doctor has advised you to have a pulmonary vein isolation (PVI) ablation as you have been diagnosed with an abnormal heart rhythm (atrial fibrillation), which has proved difficult to treat with medication. A PVI ablation will regulate your heart rate and provide relief from the symptoms you have been experiencing. This procedure stops the fast, irregular impulses from the atria, the upper chambers reaching the ventricles, the lower chambers.

What is pulmonary vein isolation (PVI) ablation?
The four pulmonary veins are blood vessels that carry blood from the lungs back to the left atrium. Doctors have discovered there is a narrow band of muscle tissue around each of the pulmonary veins near to the opening of the left atrium that may trigger the extra electrical signals that cause atrial fibrillation. Pulmonary vein isolation is a catheter ablation technique whereby the doctor uses radiofrequency energy (heat energy) to destroy this small area of tissue. The use of radiofrequency energy causes scar tissue to form. The resulting scar tissue blocks the extra electrical signals from the pulmonary veins reaching the left atrium so the area can no longer generate or conduct the fast, irregular impulses. This process is repeated around the opening of each of the four pulmonary veins. This procedure is performed under a local anaesthetic, with sedation, which will help you to relax.

The procedure is undertaken in a special room called the EP lab using X-ray screening; therefore, if you think you may be pregnant you should let us know before the procedure.

Is the pulmonary vein isolation ablation safe?
Yes, the pulmonary vein isolation is safe however, with any procedure, there are potential risks. The risks will be fully explained by our doctors before you have your procedure.

Risks of the procedure
Although the majority of patients who undergo pulmonary vein isolation do not experience complications, it is important that you are made aware that on rare occasions there are some risks associated with the procedure that may occur either during, or after the procedure. If you are known to have underlying coronary heart disease the procedural risks are slightly increased.

It is important for you to remember that the risks outlined below can be treated and are rarely life threatening.

In our experience complications associated with this procedure are very rare.

At the time of the procedure

  • Occasionally, the catheter electrodes can accidentally damage the blood vessels when being moved into position within the heart. The risk of this happening to you is between 3%-5%. Serious injury to the blood vessels requiring a surgical procedure to repair the damage is extremely rare and occurs in less than 1% of patients. 
  • During the procedure it is necessary for your doctor to make a small hole in the heart (transeptal puncture) to access the pulmonary veins, which are on the left side of the heart. This hole will usually seal up quickly after the procedure however, very occasionally the hole remains open, if this happens to you may need surgery to close it.
  • Very rarely, when your doctor makes the small hole in your heart (transeptal puncture) to access the pulmonary veins, on the left side of your heart the catheter electrodes may puncture a major blood vessel. If this happens you will require emergency cardiac surgery to close it.
  • During placement the catheters may puncture the heart muscle causing blood to collect around the heart, this is called a cardiac tamponade. If this happens the doctor may need to insert a drain to remove it. The risk of this happening to you is around 5%
  • Very occasionally, the catheter electrodes can puncture the lung wall. Air leaks out of the lungs and collects in the space between the lung and chest wall, resulting in partial or complete collapse of the lung. This is called a pneumothorax.  If this happens the doctor may need to insert a drain to reinflate your lungs. The risk of this happening to you is less than 1%
  • Again, very occasionally the catheter electrodes can puncture the lung wall. Blood leaks out of the lungs into the pleural cavity, the space between the lungs and the walls of the chest. This is called a haemothorax. If this happens the doctor will need to insert a drain to reinflate your lungs. The risk of this happening to you is less than 1%.
  • The risk of developing blood clots that travel to the lungs (pulmonary embolism), brain (stroke) or lower leg (DVT) is extremely rare, less than 1%.

After the procedure

  • Bruising and bleeding in the groin is common following the procedure. However, this usually disappears within a week and does not cause a problem.
  • It is important for you to remember that the PVI ablation procedure is not always successful. Your doctor will discuss the success rate with you on an individual basis before you sign your consent form. If the procedure is unsuccessful it may be possible to repeat it at a later date.

In the early days of PVI ablation the radiofrequency energy was delivered inside each of the pulmonary veins which resulted in some patients experiencing narrowing (stenosis) of the pulmonary veins. Today, the practice is to deliver the radiofrequency energy to the tissue around the opening of the pulmonary veins therefore, the risk of pulmonary vein stenosis (narrowing) is extremely rare.

Please remember, it is not uncommon to experience palpitations (extra heart beats) on and off for a few weeks after the procedure, until the small scars created in the heart heal. Sometimes, you may also feel as if your abnormal heart rhythm is returning, but then it suddenly stops. These sensations are normal and you should not be alarmed. However, if you feel your abnormal heart rhythm has returned, you should call your GP.

Before admission
If you are taking medication to control your heart rhythm you may continue to take your tablets before the procedure. Again, if you are taking warfarin (blood thinner) it is very important you check with your doctor before your admission. Depending on your consultant preference, you may either be asked to stop taking warfarin before you have the procedure and come in to hospital a couple of days earlier to allow the doctors to check your INR or continue to take it until the day of your date for procedure. If you are asked to remain on warfarin we do ask you to keep your INR between 2.0-2.5 before your admission.

Before the procedure, your doctor will run a number of tests to check that you do not have any blood clots in the top chambers of your heat (atria) or any other structural heart problems. These tests will include a magnetic resonance imaging scan (MRI) and sometimes a transoesophageal echo (TOE). Your doctor will also ask you to have an ECG prior to your admission at your local GP surgery to check your heart rhythm as the PVI ablation will be performed when you are in sinus rhythm, this is because the electrical signals around the pulmonary veins are easier for the doctors to see when your heart is beating normally. If you are in atrial fibrillation you will need to have a cardioversion (electric shock treatment) to restore your heart to a normal rhythm before the procedure can be performed. If you do need this treatment your doctor will give you more sedation, to make you sleepy, as a cardioversion would never be done when you are awake.

Before the procedure
On your arrival to the ward you will be introduced to the nurse who will be looking after you. The nurse will talk to you and your family about your hospital admission and answer any questions you may have. Before the procedure, you will have blood tests taken and an electrocardiogram (ECG) recorded. A doctor will also see you and explain the procedure to you, he will then ask you to sign a consent form; this is to ensure you understand the procedure and the associated risks. If you have any worries or questions please do not be afraid to ask. It is important to tell your nurse or doctor if you have any allergies or have had a previous reaction to drugs or other tests. If you are having the procedure done under a general anaesthetic, you will also talk to an anaesthetist.

Before the procedure a nurse will help to get you ready. The doctor or nurse will need to insert a small needle into a vein in your hand (cannula) this is to allow the doctor to give you drugs during the test. You will also be asked to shave your groin and if appropriate, your upper chest. You will then be given a hospital gown to wear.
You will be asked not to eat or drink anything for 4 hours before your procedure. If you are diabetic, your nurse will discuss your tablets/insulin dose with you, because not eating may affect your blood sugar levels.

Please tell your family that the PVI ablation may take between 2-4 hours so that they do not worry.

During the procedure
You may feel very anxious during the procedure, however the staff involved in your care are aware of your possible anxieties. Whilst you are in the catheter lab a nurse will stay with you and be there to reassure you throughout the procedure. There is a lot of equipment in the room, which is used to monitor your heart rhythm. You will be awake during the procedure however; to help you relax your doctor will give you a short acting sedative.

The doctor will inject a local anaesthetic into your groin to numb your leg, this may sting a little and you may feel some mild discomfort. When the local anaesthetic has taken effect, the doctor will insert a small tube (sheath) into your groin, you should not feel any pain, if you do, please let your doctor know. Through the sheath the doctor will gently thread several flexible wires (catheter electrodes) into your heart, these special wires will record and ablate (destroy) the extra electrical signals from around the pulmonary veins. The catheters are about the size of a small drinking straw. The catheters are carefully moved into position; the doctor will make a small hole (transeptal puncture) in the right atrium, the top chamber of your heart to gain access to the pulmonary veins on the left side. This is performed under under x-ray screening. You should not feel pain during this part of the procedure. Once the ablation catheter is in place, the doctor will pinpoint the area where the pulmonary veins join with the left atrium. He will then deliver a small amount of radiofrequency energy (heat energy) directly onto this area of extra electrical activity in a circular pattern to create a scar.

This process is the repeated around each of the pulmonary veins to block the extra electrical signals from the pulmonary veins reaching the left atrium.
You may feel a slight burning sensation or heaviness in your chest during this part of the procedure. It is important to remember that the formation of scar tissue as a result of radiofrequency ablation will not interfere with the normal conduction or function of the heart. Scar tissue cannot transmit electrical impulses therefore, after ablation your heartbeat will only follow the normal electrical pathway.

If you do have any uncomfortable symptoms during the procedure, for example, chest pain, dizziness, shortness of breath, please tell your nurse or doctor.

After the procedure is completed the catheter and IV line will be removed. Firm pressure will be applied to your groin where the catheter was inserted to stop you from bleeding.

After the procedure
After the procedure you will be moved to the recovery area where you will be monitored for a short time before returning to the ward. On return to the ward you will need to rest for a few hours. You may feel a little sleepy until your sedation has worn off. The nurse will record an ECG, check your blood pressure, pulse and feel your foot pulses. The nurse will also check your groin for any bleeding. It is important that you remain in bed for approximately two hours after the catheters have been removed. You should also try to lie still and avoid bending your affected leg; this is to prevent any bleeding from the puncture site. You can however rotate your ankle and flex your foot, this will help your circulation and reduce your risk of developing a blood clot (DVT) in your lower leg (calf). After this time of rest, you will be able to get up. On return to the ward you will be able to eat and drink normally. The nurse will remove the small needle in your hand. If you feel any palpitations or dizziness after the test, please let the nurse know. You will also have a chest x-ray to make sure that you do not have a pneumothorax (pocket of air) in your lung.

When will I know the result of my procedure?
After your procedure your doctor will usually discuss the results and treatment plan with you and your family.

Your discharge
You will normally be able to go home the following day. It is important to ask a family member or friend to collect you and drive you home. Prior to your discharge, your doctor or EP nurse will advise you regarding the medicines you will need to take, or stop and your follow-up care.

Caring for your wound
You will have a small dressing on your puncture site that can be removed the next day. It is important to keep the area clean and dry until it has healed. If you notice any swelling, redness or oozing please let your GP know.

When can I resume my normal activities?
You can resume your normal daily activities (walking, bathing, showering, etc.) upon discharge from hospital. The only restriction is straining or lifting heavy objects for a few days so that the incision site can heal.

When can I go back to work?
Unless your job requires you to lift heavy objects, you can return to work in a day or two.

Will I still need to take medication?
After the procedure all your antiarrhythmic tablets may be stopped.
Warfarin will be continued for 3 months, occasionally longer if you experience a repeat episode of atrial fibrillation. On average, it takes about three months for the heart to fully recover. You may experience atrial fibrillation and palpitations (skipped heartbeats) whilst in hospital and in the first 2 – 3 months after the procedure, this does not mean the abaltion has failed. If this happens your doctor may give you medicines to stop your arrhythmia and keep you anticoagulated on warfarin. If during this period, if you continue to experience atrial fibrillation and feel unwell your doctor may suggest you have a cardioversion to regulate your heart rhythm.
The atrial fibrillation and palpitations will gradually decrease. Three months after the procedure the majority of patients are in normal sinus rhythm and your doctor will ask you to stop taking your medications.

It is important to remember however that approximately two thirds of patients respond to pulmonary vein isolation with one third requiring a repeat procedure.


The DVLA's guidance is that after a PVI ablation you should not drive a car for 1 week. If you hold a Group PSV 2 licence (lorries/buses), you are not able to drive for 6 weeks.

Will I come back here for follow-up?
Upon discharge from the hospital, you will receive specific follow-up instructions by our Electrophysiology team. Our doctors will write a detailed letter to your GP detailing your hospital stay and treatment.

Heart Rhythm Clinic


Launch of Heart-Holidays
Heart Rhythm Clinic have established a strategic liaison with Travelux holidays to provide supported...

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Heart Rhythm Clinic


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023 8091 4490

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Heart Rhythm Clinic
Heart Rhythm Clinic

Heart Rhythm Clinic
Spire Southampton Hospital, Tremona Road, Southampton SO16 6UY   Tel: +44 (0) 23 8091 4490   Fax: +44 (0) 23 8091 4490   E-mail: