Welcome to London Heart Clinic’s cardiac ablation patient guide

Read this guide to find out: 

  • If you are at risk from abnormal heart rhythms
  • How cardiac ablation works
  • The benefits and risks of ablation
  • How to prepare and recover

This guide includes explainer videos on key topics. Watching these will help you make an informed choice about your care. 


What is ablation?

In a healthy heart, the rhythm is steady and coordinated. As it adapts to changes in the body, it will slow down or speed up. Your heart rate affects how much blood and oxygen circulate around your body.

Some people’s hearts develop abnormal cells that disrupt electrical signals. The heart doesn’t beat how it should, and the person experiences abnormal heart rhythms (arrhythmias).

Medicines can help control the abnormal tissue that causes arrhythmias. However, they are not effective for everyone, can cause side effects, and don’t solve the underlying problem.

The cardiac ablation procedure corrects arrhythmias by treating tissue with targeted energy. This restores normal function and eliminates the symptoms. 

Using this minimally invasive, drug-free approach, we can deal with arrhythmias that are difficult to treat with medications.

Ablation normally uses catheters (small tubes) placed into the heart through a blood vessel. This is also called catheter ablation

Once we identify the tissue involved in the heart arrhythmia, we target it by heating or cooling the area. This makes small scars in your heart (ablation lines), which stop arrhythmic electrical signals from passing along the nerve pathways. 

Dr. Syed Ahsan discusses the catheter ablation procedure in this video.

What is heart ablation used for?

Doctors use cardiac ablation to treat arrhythmias and certain structural heart disorders. We group these into four main types, explained further below: 

  1. Supraventricular arrhythmias
  2. Ventricular arrhythmias
  3. Cardiomyopathy
  4. Congenital heart disease

Conditions treated

Read on to learn more about the conditions heart ablation can treat:

Supraventricular arrhythmias

Atrial fibrillation (Afib or AF)

The atria and ventricles are the body’s basic heart-muscle pumps. The atria (the two upper heart chambers) collect blood from the heart’s two ventricles (the two lower heart chambers) and pump it around the circulation system. 

When the atria undergo atrial fibrillation, they don’t contract in a coordinated way. So they can’t push blood into the ventricles. 

Instead, the atria ‘quiver’ and blood pools within them. This makes it difficult for the heart to pump blood around the body.

In AF, your heart beats fast and irregularly (also known as palpitations). If blood pools in the upper chambers as a result, it creates a shortage of oxygen-rich blood. 

AF increases the risk of stroke and heart failure. It can also cause dizziness, palpitations, or fainting

People over 65 are most at risk of developing AF. Diet and lifestyle may play a role, but often, they have unknown causes. If you’ve had high blood pressure or coronary heart disease for a long time, this may increase the risk of AF.

Managing AF is a two-pronged effort that requires lifestyle changes and following the right treatment plan. You can reduce risk by maintaining a healthy weight, exercising regularly, and eating healthily. Find out more about how to change your lifestyle to aid your heart health here.

The first treatment for atrial fibrillation is normally medication to prevent strokes and control heart rhythm. 

Other options include electrical cardioversion (a small, controlled electric shock), cardiac ablation or a pacemaker.

Watch this animated video to learn everything you need to know about atrial fibrillation.

Atrial flutter

Atrial flutter is when your atria beat much more quickly than usual. The top of your heart beats faster than the bottom. This causes an abnormal heart rhythm.  

Atrial flutter is less common than atrial fibrillation but may share symptoms, causes, and complications. Some people have both.

Symptoms can include palpitations, shortness of breath, and feeling faint. It may happen due to underlying health issues, lifestyle problems, or as a side effect of heart surgery. 

With atrial flutter, cardiac ablation is considered the best treatment. 

Watch this video to learn everything you need to know about atrial flutter.

Supraventricular tachycardia (SVT)

Your heart will beat quickly during physical activity, stress or fever – this is normal. SVT is an abnormally very fast but regular heartbeat of more than 100 beats per minute.

The main symptom of SVT is a high heart rate. Some people experience tightness or pain in the chest. You may also be dizzy, breathless, light-headed, flushed or sweaty. A pounding pulse or palpitations are also possible signs of an SVT condition.

SVT is a dysfunction in the heart’s electrical impulses caused by congenital defects or a complication after heart procedures. 

SVT conditions may cause the organ’s muscles to become weak and unable to pump efficiently. It can return to normal by itself or with treatment. However, if left untreated, SVT may become more severe and even life-threatening.

To manage supraventricular tachycardia (SVT) conditions, doctors may recommend simple techniques to stimulate the vagus nerve. This nerve runs down from the brain to the abdomen. Vagus nerve stimulation manoeuvres include applying an ice-cold wet towel to your face.

Fast-acting medicines or electrical cardioversion are other options for sudden SVT onsets. For chronic episodes, you may need medication or a cardiac ablation.

In this video, Dr Syed Ahsan explains how catheter ablation can help SVT.

Wolff-Parkinson-White syndrome

In Wolff-Parkinson-White syndrome (WPW), a person has an extra electrical connection between the heart’s upper chambers and main pumping chambers. 

This extra connection causes a rapid heartbeat. It may also cause irregular heartbeats and other heart problems.

Although this is a condition present from birth, symptoms may not develop until your teens or early 20s. 

Younger patients, including babies, may have fatigue and difficulty breathing or eating. In adolescents and young adults, WPW causes a racing heartbeat, fainting, and chest pains.

Simple self-administered manoeuvers stimulate the vagus nerve and help manage acute and isolated episodes. We usually recommend a cardiac ablation procedure to treat WPW syndrome if the condition keeps recurring. 

Heart rhythm monitoring is important with WPW syndrome. This is because you may develop atrial fibrillation, leading to ventricular fibrillation and possible cardiac arrest. 

Explore this playlist, Dr Syed Ahsan will explain what WPW syndrome is.

Ventricular arrhythmias

Ventricular fibrillation (VFib)

VFib occurs when the ventricles beat out of control. The ventricles quiver and are unable to pump blood properly. People with VFib are at a high risk of suffering a cardiac arrest.

VFib is extremely serious and requires immediate attention. Symptoms include a fast or irregular heartbeat, followed by a seizure and loss of consciousness caused by cardiac arrest. 

An underlying heart disorder can cause ventricular fibrillation. Examples include coronary artery diseasea heart attack, cardiomyopathies (heart muscle conditions) or structural problems.

VFib is also brought on by extreme shock, electrocution, drowning or as a side effect of medications that influence the heart’s electrical system. 

VFib is a medical emergency. If you think someone is experiencing this condition, call emergency services.

Ventricular tachycardia (VT)

Ventricular tachycardia (VT) causes the heart to exceed 120 beats per minute. It happens when one of the heart’s electrical circuits is damaged. If this continues for more than 30 seconds, it’s called sustained ventricular tachycardia.

People with ventricular tachycardia usually have general heart disease symptoms. These include discomfort in the chest, shortness of breath, palpitations and light-headedness. 

If symptoms persist, the condition affects the heart’s ability to pump normally. It can lead to a drop in blood pressure, heart failure and ventricular fibrillation. 

Medication and treatments, including cardioversion and cardiac ablation, can reduce the risk of VT returning. Ablation is among the most effective treatments for VT because it destroys the source of abnormal electrical activity.


Bradycardia is any type of heart rhythm that’s slower than normal. It can occur in people without heart disease. Extremely fit athletes, for example, will have a naturally slow heart rate.

However, in some people, it’s a sign of heart problems or another underlying condition. It can be temporary or permanent and vary in severity. It doesn’t necessarily cause symptoms and may not be dangerous unless the heart cannot pump enough blood.

Bradycardia may cause breathlessness after physical exercise, fatigue, confusion or loss of consciousness. If your heart rate is under 60 beats per minute, you may experience palpitations.

Bradycardia can be due to a variety of different health problems. They include nervous system or hormonal disorders, low body temperature, high blood potassium level, Lyme disease or typhoid fever. 

Sometimes, heart rates slow down because of medications, such as beta-blockers, used to treat high blood pressure and arrhythmias. 

The treatments for bradycardia include: 

  • A pacemaker device to correct the slow heart rhythm
  • Medication (especially when underlying illnesses cause bradycardia)
  • Cardiac ablation


Cardiomyopathy is a general description of conditions that cause the heart muscle to become abnormally thick. This makes the heart inefficient, leading to signs of heart failure, such as shortness of breath and fatigue.

Inherited genetic disorders cause most types of cardiomyopathy that affect children and younger people. However, there are other types of cardiomyopathy that occur at other ages, and sometimes the causes are unknown. 

Normally, cardiomyopathy has no cure, but treatments relieve symptoms and reduce complications. The exact treatment (including hospital procedures) depends on the type of cardiomyopathy. 

If the condition is mild, reducing stress and following a healthier lifestyle helps. However, seek the guidance of a cardiologist before attempting strenuous exercise. 

Medication may benefit patients who need to manage blood pressure and abnormal heart rates, reduce swelling or prevent blood clots.

In some cases, cardiac ablation may be recommended. However, this treatment alone doesn’t address all cardiomyopathy symptoms.

Congenital heart disease

Congenital heart disease is a general term used to describe a range of conditions present at birth that affect the heart and blood vessels. These conditions can be life-threatening if left untreated. 

Because congenital heart disease is a term that covers various heart defects, the symptoms vary. In the most severe cases, problems will be noticeable soon after birth. In others, signs don’t appear for several years. 

For babies and infants, signs to look out for include: 

  • Fast breathing and heart rate
  • Swelling (especially of the legs, belly and around the eyes)
  • Difficulty feeding 
  • A blue tint to the skin. 

For older children or adults, symptoms also involve fatigue and fainting while exercising.  

Many congenital heart diseases are mild and easily treated. Severe cases require ongoing treatment and monitoring. It’s important to understand the symptoms, treatment, and lifestyle implications of your condition.

We may advise medication, ablation or heart surgery in cases where arrhythmia problems are more dangerous. 

Is ablation right for you?

Ablation is a treatment for people with recurrent heart arrhythmias, especially where medicines or cardioversion have proved ineffective. It is not a cure for cardiomyopathy, but it can stop the heart from beating abnormally.

Ablation is an effective treatment, but it is not suitable for everyone. The procedure is not without risks (see below), and complications can occur. Your cardiologist will discuss the risks and benefits of the procedure.

In this video, Dr Syed Ahsab explains what an ablation can treat.

How is an ablation of the heart performed?

Ablation is a procedure that destroys areas of heart tissue that are causing abnormal electrical activity. 

Catheter ablation involves doctors inserting a small tube into a blood vessel and threading it to the area of the heart, causing the abnormality. The procedure is much less invasive than heart surgery.

But how long does a cardiac ablation procedure take? The procedure usually takes between two and four hours, often only under local anaesthetic.

The catheter monitors the heart’s electrical activity to ensure that doctors target the correct area. Radiofrequency ablation involves applying a mild burst of energy to the tissue. Some patients need repeat attempts.

It’s not uncommon to experience slight discomfort during the procedure. 

Cardiac ablation is sometimes performed as part of open-heart surgery, but this is rare. Ablation combined with other treatments can reduce the risk of complications. 

In this video, Dr Syed Ahsan explains what you can expect from an ablation procedure.

Cryoablation is a variation of the process. It involves a small balloon containing a material that freezes heart tissue rather than treating it with radiofrequency energy.

Watch this video to learn more about cryoablation.


Ablation can treat many arrhythmia conditions. Its benefits include eliminating symptoms like: 

This procedure can also reduce the risk of life-threatening complications such as blood clots, stroke, and cardiac arrest.

The procedure destroys abnormal heart tissue, which can vastly increase the quality of life for people with serious heart arrhythmias, including atrial fibrillation. Ablation is also used to treat cardiomyopathies, which are heart muscle diseases.

Ablation usually takes place under local anaesthetic using a minimally invasive catheter procedure. Less commonly, it’s used during an open-heart surgical operation.

Ablation may take the place of medications in cases where drugs are not effective. 

What is the success rate?

Catheter ablation is a low-risk procedure. The outcome is successful for most people who have received the treatment. It’s routinely offered to people with symptomatic AF, for example. 

Although there is variation between countries, a study in the British Journal of Cardiology showed that catheter ablation is effective in at least 80% of AF cases. 

Sometimes, patients need an additional ablation treatment. The reported success rate was 95% after a second ablation.

It’s also a highly successful alternative to antiarrhythmic drug therapy, with about 70% of AF patients not needing antiarrhythmic medication after ablation treatment. 

Explore this playlist, Dr Syed Ahsan explains the success rates for cardiac ablation.


Catheter ablation comes with a small risk of short-term complications. 

Because ablation is normally administered with a catheter, the main side effects are pain, bleeding, bruising or a later infection at the insertion point. This area may be in the groin, arm or neck. 

These effects are rare, easily treatable and do not leave patients with long-term issues.

In rare cases, patients may have an allergic reaction to the medication used during the procedure. 

According to the British Heart Foundation, with catheter ablation, there’s a one in 200 chance of bleeding around the heart (treated by draining). 

The risk of having a disabling stroke due to blood clots is about one in 500. The risk of death is about one in 1,000. 

Some patients may need a pacemaker. This can happen if the ablation targets the atrioventricular (AV) node or if the heart’s electrical system is damaged. 

In some cases, patients need an implantable cardioverter-defibrillator (ICD). 

Other rare but possible complications include: 

  • Damage to blood vessels due to the catheter scraping them
  • Damage to heart valves or other structures
  • Damage from radiation used during fluoroscopy (X-rays that show moving images for catheter guidance)
  • Damage to kidneys from fluoroscopy dye
  • Narrowing of veins that carry blood between the lungs and heart (pulmonary vein stenosis)
  • A new or intensified arrhythmia
  • Blood clots in legs or lungs (venous thromboembolism)

You should assess these against leaving your heart condition untreated, which comes with its own dangers. Your cardiologist will discuss all of these points with you. 

In this video, Dr Syed Ahsan explains the risks of ablation.


Some patients will need to begin taking a blood thinning medication for a few weeks before and after the procedure. This reduces the risk of blood clots. You may have a few tests so the doctors have as much information as possible about your condition before the ablation. 

You should stop eating and drinking at least six to eight hours before the ablation. Doctors will tell you if you can continue prescription medications before the ablation. For example, if you’re on antiarrhythmic drugs, you should stop them a few days before. If you already have a pacemaker or ICD, you’ll get special instructions. 

Make arrangements for someone to drive you home after your ablation. 

Immediately before the procedure, the team gives you an intravenous sedative to make you relax. Sometimes, patients need general anaesthesia. The medical team will clean, shave, and numb the catheter insertion area (usually the groin, arm, or neck). They insert a needle into a blood vessel and place a small tube sheath into it. Catheters go through the sheath and along the vein (or sometimes an artery) to your heart. 

Doctors use electrodes or fluoroscopy to guide the catheters to the right area. In fluoroscopy, they inject a dye into a blood vessel and follow it with a live X-ray. 

The wires in the catheters send small electrical impulses. First, this activates the area of heart tissue, while other catheters measure the results. This part of the process, called an electrophysiology study, pinpoints the source of abnormal heart rhythms. 

Then, doctors place a catheter at the precise point of the abnormal cells and send a mild pulse of radiofrequency energy – it’s like using a miniature microwave oven. This is painless and destroys the abnormal cells in a very specific area, leaving the rest of the heart unaffected. 

A variation of the process (cryoablation) uses a substance on the end of the catheter to emit extreme cold instead of heat. 

The whole process usually takes between two to four hours. Ablation carried out during open-heart surgery is much more complicated. Surgeons will do this if you need surgery for other aspects of your heart problems.


After ablation, you’ll see bruising and feel tender around the catheter insertion point. 

Hospital staff will monitor you after the procedure to ensure it was successful. You’ll need to lie down and remain still in a recovery area for a few hours for observation. Depending on your condition, you can usually go home the same day. 

How long it takes to heal after heart ablation varies according to the type of arrhythmia and its treatment. You should rest for a few days and not drive for two days.

After a week, the tenderness around the catheter insertion site should decrease.

In the first few days after the ablation, you should avoid heavy lifting and other physical exertion. You can take cool showers, but avoid bathing and swimming until the incisions heal.

Gradually increasing your amount of physical exercise usually helps. Brisk walking by the second week is normal. 

You may still feel some heart symptoms for a few weeks, such as palpitations. 

Within the first two months, your doctor will discuss whether the ablation was successful and whether you can stop taking any of your medications. 

For surgical ablation, you will spend up to about a week in the hospital, with the first day or two in an intensive care unit. 

The recovery time will also be longer and depends on the exact surgical procedure. It takes several weeks to get back to normal, or in the case of open-heart surgery, up to six months. 

In this video, Dr Syed Ahsan explains how long it takes to know if your ablation was successful: 


A cardiac ablation improves the quality of life for most patients. Symptoms like heart palpitations and chest pain should disappear, and your risk of life-threatening arrhythmias will be greatly reduced.

People who’ve had an ablation should always inform their cardiologist of any new symptoms or irregularities. These could be signs that the procedure has been unsuccessful or that another problem has arisen.

In this situation, you may need another ablation or continue taking medication. 

It’s normal for some patients to experience mild chest discomfort for a few days and irregular heartbeats (arrhythmias) for up to about eight weeks. 

Contact your doctor if you have any of the following after ablation: 

  • Increased bleeding, bruising, pain, numbness or swelling at or near a catheter insertion site
  • Chest pain
  • Shortness of breath
  • Nausea
  • Excessive sweating
  • A temperature over 38 degrees C
  • Persistent arrhythmia
  • Light-headedness
  • Confusion
  • Signs of stroke

Call 999 if the catheter insertion site swells rapidly or bleeds and doesn’t stop after you press down on it. 

Keeping your heart healthy

As part of your treatment, you should follow general health advice to help your heart recover and reduce the risk of complications. 

Here are a few tips to support a full recovery from cardiac ablation: 

  • Try to keep active, but avoid straining or overdoing things
  • Drink plenty of water and eat a healthy diet
  • In particular, limit salt, alcohol and caffeine
  • Don’t smoke
  • Maintain a healthy weight
  • Manage stress and anxiety levels, which can make heart symptoms worse
  • If you’re prescribed blood thinners or other medications, please take them as instructed
  • Be sure to attend any follow-up appointments and share any concerns with your doctor.

In this video, Dr Syed Ahsan explains the most important factors for maintaining a healthy heart:

How to book a cardiac ablation

Ablation can be a life-changing procedure for those with serious heart conditions. 

For more information on heart ablation, contact us to book a consultation appointment.

Useful questions to ask the specialist are:

  • What is the cause of my heart arrhythmia?
  • Will catheter ablation help me with my symptoms?
  • Are there other treatments to think about?
  • Am I likely to need another procedure after catheter ablation?
  • Will I have to keep taking medication after ablation?

By taking the right precautions and preparing for the procedure, you can ensure a safe and successful outcome.