Atrial Fibrillation Ablation
What is Catheter Ablation?
Catheter ablation is a minimally invasive, keyhole technique used to treat a variety of heart rhythm disorders. It is performed in a special operating theatre called a cardiac catheterization laboratory, or cath lab for short. A catheter is a fine wire that can be threaded through a blood vessel via a keyhole opening in the skin and placed in the heart. Usually, a blood vessel at the top of the right thigh in the groin area is used for access to the heart.
Depending on the complexity of the arrhythmia, up to 4 catheters may be used during the procedure. Each catheter has electrodes on its end that can monitor the heart’s internal electrical activity, akin to performing an internal ECG of the heart. An ablation catheter can be used to deliver radiofrequency energy to the problem area in the heart. Radiofrequency energy is a low power, high frequency energy that is delivered to a tiny region of heart tissue near the tip of the catheter, thus cauterizing or ablating the tissue.
Radiofrequency energy has been used for decades by surgeons to cut tissue and to stop bleeding. For the treatment of heart rhythm disorders, radio-frequency energy at a much lower power is used to ablate tissue within the heart that is responsible for initiating or perpetuating your arrhythmia.
AF ablation is designed to cure your symptoms and improve your quality of life. However, because the procedure carries a number of small but important risks, it is recommended only to those people having frequent episodes of AF or continuous AF where there is a significant impact on quality of life. AF ablation is also recommended if AF has resulted in deterioration of the heart’s pump function, even in the absence of symptoms.
Otherwise, AF ablation is not recommended for people who have minimal symptoms or who feel that the condition represents only a relatively minor nuisance. Here, a wait and see approach or a trial of medications is normally recommended first as many individuals will be well controlled on tablets.
This is normally an elective procedure. You will receive a letter from the hospital bookings clerk or doctor’s secretary outlining the date, time, and other details of your hospital admission. A nurse may call you to confirm your personal and medical details.
You will normally require a blood test and a CT or MRI heart scan in the week prior to your procedure. The scan helps guide the ablation, but in some cases is not essential for the ablation to proceed.
You will receive specific instructions about any medication changes that are necessary prior to your procedure. If you are unsure about the instructions, please do contact the clinic for clarification.
You must fast for at least six hours before your ablation. If your procedure is in the morning or early afternoon, do not eat or drink after midnight, except for a sip of water to help you swallow your pills.If your procedure is in the mid to late afternoon, you may have a light, early breakfast.
You will be admitted to a hospital bed on the day of your procedure.You will be provided a hospital gown. Pre-operative checks will be performed and your groin area will be shaved before transfer to the cath lab. The cath lab has a movable patient bed, an X-ray machine, ECG monitors, and other equipment.
ECG electrodes and patches will be attached to your chest and back. These will feel cool on your skin. An anaesthetist will insert a fine intravenous tube usually into the back of your hand before administering the general anaesthetic medication. A second tube will be placed into the artery of your wrist to monitor blood pressure.
The entire AF ablation procedure will then be performed while you are asleep under general anaesthesia. This will normally take 1.5 hours depending on the complexity of your procedure.
While you are under anesthesia, a transoesophageal echocardiogram (TOE) will be performed. This involves an ultrasound probe that is passed down your throat to provide detailed pictures of year heart which sits just in front of the gullet.
Intravenous lines will be placed in a vein at the top of the right thigh in the groin area through which catheters will be passed and positioned in the heart. Rarely, a vein in the neck may also be required to access the heart.
The electrical catheters are positioned using X-ray, ultrasound, and a computerized 3D mapping system to guide placement. These electrical catheters first enter the right atrium. Because AF begins in the left atrium, a needle is required to cross from the right to the left side through the thin membrane that divides the 2 upper chambers. This will be performed using X-ray, ultrasound, and pressure-monitoring guidance. This part of the procedure is called the “transseptal puncture”. After the procedure, the defect in the membrane seals off on its own.
In AF, abnormal electrical activity can originate from any of the pulmonary veins. Thus, the atrial tissue around these veins is ablated to prevent any electrical impulses from leaving the veins and triggering AF. If you have persistent AF, additional ablation may be required to address other areas responsible for perpetuating AF. Following ablation, further testing is performed to conclude the procedure.
AF ablation has been developed over 2 decades and is now a routine procedure in many hospitals around the world. Although most people undergoing AF ablation do not experience any complications, you should be aware of the following possible risks.
There is a 1% (1 in 100) combined risk of a major complication, including though not limited to the following.
- Stroke or heart attack.
- Cardiac perforation, vascular injury, or heart valve injury that may require urgent open heart surgery to correct.
- Bleeding from the groin vascular access site or damage to the adjacent artery which may require blood transfusion or surgical correction.
- Damage to the normal electrical system of the heart resulting in a permanent pacemaker.
Very rare complications occur in <0.1% (1 in 1000) and include the following.
- Damage to nerves supplying the diaphragm or stomach.
- Damage to the eosophagus.
- Pulmonary vein stenosis (narrowing the blood vessels that enter the left atrium).
Minor complications occur in 5% (1 in 20 chance) with full recovery expected. These include the following.
- Groin problems where the electrical catheters are inserted: bleeding, blood clot, bruising, or infection. Occasionally there may be numbness on the front of the leg.
- Positional chest pain affected by breathing due to irritation of the surrounding membrane of the heart. This normally settles down over a few days with a course of painkillers and anti-inflammatory medications if severe.
If there is a chance you are pregnant, please notify the doctor performing the procedure.
You will wake up in the recovery ward before being transferred to a normal hospital ward. There will be a pressure cushion at the access site in the right groin which will remain in place for around 2-4 h. You will recover in bed for at least 3 hours after the procedure. During this time, it is important to keep your legs straight and your head relaxed on the pillow. If you have had trouble emptying your bladder, you may also have a urinary catheter in place which may be removed once you are ready to get out of bed.
It is usual to stay in hospital for 1 nights after the procedure. Your heart rhythm will be monitored during this time. You will be prescribed the following medications:
- Blood thinner.You will require an 8 week course to prevent blood clots in the heart. Depending on your situation, you may need to continue your blood thinner for longer.
- Antiarrhythmic medications. Your usual antiarrhythmic medications may be continued for 8 weeks before these are reduced and subsequently stopped.
After the procedure, it is common to have a sore throat and some mild chest discomfort. You may also have some discomfort and bruising in the groin. Symptoms will typically improve over several days. You should avoid exercise, driving, and heavy lifting for at least 5 days after the procedure. Please arrange to take 1 week off work and driving for your recovery.
You may experience a migraine accompanied by flashing lights or blind spots. While you might be alarmed, you are not having a stroke. Migraines are common after the procedure and generally pass after a week or so.
Some individuals experience bloating and indigestion due to irritation of the gullet or a nerve near the heart called the vagus nerve. This normally settles after a week or so.
Because it takes several weeks for the areas of ablation to heal and form scars, it is not uncommon to experience abnormal or irregular heartbeat or rhythm for up to 8 weeks after the procedure. Rarely, palpitations may be worse for a few weeks after the procedure due to inflammation where the ablation was performed. This is the reason why antiarrhythmic medications are typically continued for 8 weeks post-ablation.
You may notice that your resting heart rate increases following AF ablation to 80-90 beats per minute. This occasional side effect has no ill effects and may take 6 to 12 months to normalize.
You will be issued further discharge information and instructions which can be found here. It is important that you read and retain these instructions with you for 8 weeks following discharge. You will need to arrange for a family member or friend to pick you up from the hospital once you are discharged. A follow-up appointment will be arranged 8 weeks post-procedure or earlier if necessary.
Information for Patients
- Wound care.The puncture site at the top of the right thigh in the groin area will take approximately 1 week to heal. Observe the area every day and keep it dry and clean. Avoiding applying soap and talcum powder to the site. A pea-sized lump and a minimal amount of bruising is normal and may last for up to 2 weeks.If there is increasing pain, active bleeding, or an expanding mass in the groin, please make immediate contact with the clinic, or proceed immediately to your local emergency service for assessment, bringing this information sheet with you.
- Rest and recovery. To best facilitate healing of the puncture site, take at least 1 week off work. Avoid exercise, driving, abdominal straining, and heavy lifting for 5 days. Rest and gentle walking at home is permitted. After 5 days, slowly return to normal activities. After 1 week there should be no limitations on your usual activities.
- Palpitations. You may develop recurrent palpitations during the 8 week healing period. If these come and go on their own, they are best managed with medications. If they are continuous over >24 h, please contact the clinic as it may be necessary to arrange a small electric shock to restore normal rhythm.
- Red flag symptoms. Mild chest pain that is worse with lying down or breathing in is normal following your procedure and will resolve over 1-2 weeks. However, if you develop a fever with temperature >38C, weakness or numbness of a limb, difficulty speaking, difficult or painful swallowing, vomiting, or passing blood, please make immediate contact with the clinic, or proceed immediately to your local emergency service, bringing this information sheet with you.
- Contact details. Prior to your first follow-up appointment, it is best to contact the treating team for any post-procedure issues rather than your GP or general cardiologist who may not be so familiar with details of the procedure. For public patients, contact the Alfred Heart Centre on 03 9076 3263. For private patients, contact the Heart Rhythm Clinic on 03 8560 0535. If the clinic is closed or the treating doctor or nurse not available, please proceed to your GP or local emergency service for evaluation.
Information for Doctors
This patient has undergone radiofrequency catheter ablation for atrial fibrillation, and may present with one of the following issues. Should you have any concerns, please do not hesitate to contact Dr Han Ling through the Heart Rhythm Clinic on 03 8560 0535 or through the Alfred Hospital Switchboard on 03 9076 2000.
- Vascular access issues. The ablation procedure typically involves 4 sheathes placed in the right femoral vein with continuous perioperative anticoagulation. Femoral arterial access is not required. Ongoing issues with bleeding are therefore normally easily addressed with manual compression. However, if there has been increasing pain or and expanding mass, please consider ultrasonography to exclude AV fistula or false femoral aneurysm in the unlikely event of unrecognized arterial injury.
- Recurrent atrial arrhythmia. If the patient presents with AF or atrial flutter in the first 2-3 months post ablation, TOE-DCR would be beneficial if this could be accommodated in the emergency department setting. Documentation of the arrhythmia is essential for future planning. Kindly provide a hard copy of the discharge summary and relevant ECG traces to the patient and to fax: 03 8080 6460.
- Atrioeosophageal fistula. A rare (<1:1000) but extremely serious complication of this procedure is atrio-oesophageal fistula. This can develop slowly, and usually occurs within 6 weeks post procedure. Presentation typically involves fever (T>38 C) in combination with stroke, chest pain, difficult or painful swallowing, vomiting, or passing blood.Under no circumstances should the patient have their oesophagus instrumented with upper GI endoscopy, transoesophageal echocardiography, etc. The test of choice for diagnosing the problem is a CT chest with IV contrast done in an experienced centre.
The success rate varies from case to case according to a number of factors. General figures are provided below, but your doctor will provide a more detailed estimate based on your clinical situation. One of the key factors is the type of AF that you have.
In general, the following success rates apply.
- Paroxysmal AF (AF starts and stops by itself within 7 days) – The overall success rate is 85%, although to 1 in 4 patients may require second procedure for arrhythmia recurrence. After 2 technically successful procedures, up to 15% of patients may continue to have some symptoms.
- Persistent AF (AF continues for > 7 days or doesn’t ever stop without an electrical shock) – The overall success rate is 75%, although up to 1 in 3 patients may require a second procedure for arrhythmia recurrence. After 2 technically successful procedures, up to 25% of patients may continue to have some symptoms. If your AF has been continuous for more than a year, the success rate is lower and this will be discussed with you.