Catheter ablation for atrial fibrillation

Treatment Overview

If medicine is not effective or not tolerated for atrial fibrillation, a nonsurgical procedure called catheter ablation may be chosen. Catheter ablation for atrial fibrillation is relatively new and is still being studied.

In this procedure thin, flexible wires are inserted into a vein in the groin and threaded up through the vein and into the heart. There is an electrode at the tip of the wires. The electrode sends out radio waves that create heat. This heat destroys the heart tissue that causes atrial fibrillation or the heart tissue that keeps it happening. Another option is to use freezing cold to destroy the heart tissue.

Ablation procedures either try to cure atrial fibrillation (focal ablation, circumferential ablation, and pulmonary vein ablation) or try to control your symptoms (nodal ablation).

Ablation to cure atrial fibrillation

Focal and circumferential catheter ablation are used to try to cure atrial fibrillation. Focal ablation, also known as targeted ablation, is used to destroy the specific areas in the heart that are firing off abnormal electrical impulses and causing atrial fibrillation. Circumferential ablation is used to destroy the tissue that lets atrial fibrillation continue. Sometimes, a doctor uses both focal and circumferential ablation.

Pulmonary vein ablation is also used to try to cure atrial fibrillation. Sometimes, abnormal impulses come from inside a pulmonary vein and cause atrial fibrillation. (The pulmonary veins bring blood back from the lungs to the heart.) Catheter ablation in a pulmonary vein can block these impulses and keep atrial fibrillation from happening.

A pacemaker is usually not needed when catheter ablation is done on the pulmonary vein or other targeted tissue.

View a slideshow of pulmonary vein or focal ablation to see how the heart's electrical system works, how atrial fibrillation happens, and how pulmonary vein or focal ablation is performed.

In some cases, catheter ablation may be done by applying radiofrequency energy to the outside or inside surface of the heart during open-heart surgery. This may be an option if you are already having heart surgery for another reason, such as coronary artery bypass or valve replacement surgery.

Ablation to control symptoms of atrial fibrillation

Nodal catheter ablation, also known as AV node ablation, can control symptoms of atrial fibrillation when the cause cannot be stopped. You may need AV node ablation if targeted or pulmonary vein ablation did not stop your atrial fibrillation, or if these procedures will not help you. With AV node ablation, the entire atrioventricular (AV) node is destroyed. After the AV node is destroyed, it can no longer send impulses to the lower chambers of the heart (ventricles). This controls atrial fibrillation symptoms.

After AV node ablation, a permanent pacemaker is needed to regulate your heart rhythm. Nodal ablation can control your heart rate and reduce your symptoms, but it does not prevent or cure atrial fibrillation. So you will probably need to take anticoagulation therapy such as warfarin.

View a slideshow of AV node ablation to see how the heart's electrical system works, how atrial fibrillation happens, and how AV node ablation is performed.

You will be given medicine to help you relax. A local anesthetic will numb the site where the catheter is inserted. The procedure is done in a hospital where you can be watched carefully.

What To Expect After Treatment

Recovery from catheter ablation is usually quick. You may be hospitalized for 1 to 2 days so that your doctor can monitor your heart rate. After the procedure, you will need to take anticoagulation medicine, such as warfarin (Coumadin, for example) for at least 3 months.

You might feel a flutter in your heart after the ablation procedure. The flutter usually goes away after your heart heals. If your flutter does not go away, you may need a second ablation procedure.

Why It Is Done

Focal ablation or pulmonary vein ablation that targets tissues that generate irregular electrical impulses is often used for paroxysmal atrial fibrillation in people who have severe symptoms and who have not been helped by medicines.

AV node, or nodal, catheter ablation is sometimes used when persistent chronic atrial fibrillation does not respond to treatment with medicines and symptoms continue to be bothersome. It is most often used in people who have difficult-to-control heart rates.

How Well It Works

Catheter ablation is more successful in people who have atrial fibrillation that comes and goes (paroxysmal) than in people who have atrial fibrillation that is persistent or chronic (constant).

• Research shows that ablation helps 80 out of every 100 people who have atrial fibrillation that comes and goes (paroxysmal). That means it does not help in 20 out of 100 cases.¹
• Ablation works for about 60 out of 100 people who have persistent or chronic (constant) atrial fibrillation. That means it doesn't work in 40 out of 100 cases.¹

If the first procedure does not get rid of atrial fibrillation completely, catheter ablation may need to be done a second time. Repeated catheter ablations have a higher chance of being successful.

Catheter ablation is still being studied to see how well it works and how safe it is in the long term.

Risks

Catheter ablation to cure atrial fibrillation is an invasive procedure and has some serious risks. These risks include:

• Stroke. A stroke is a sudden disruption in blood flow to a portion of the brain. The disruption in blood flow is caused by a blockage or by bleeding of a blood vessel.
• Heart attack.
• Puncture of the heart.
• Need for emergency heart surgery.
• Damage to the pulmonary vein.
• Pulmonary vein stenosis, which is a narrowing of the pulmonary vein.
• Phrenic nerve injury, which can cause paralysis of the diaphragm. The diaphragm is a large muscle that separates the chest cavity (containing the lungs and heart) from the abdominal cavity. It helps draw air in and out of the lungs.
• Pericarditis. Pericarditis is inflammation of the sac (pericardium) that surrounds and protects the heart.
• Cardiac tamponade. This is an emergency condition that can lead to death. It may require emergency heart surgery.
• Atrio-esophageal fistula. In this life-threatening condition, a hole forms between the heart's upper chamber and the esophagus.
• Bleeding from the puncture site where the wires are inserted.
• New abnormal heart rhythms (arrhythmias).
• Sudden death.

The risks of catheter ablation of the AV node include:

• Bruising.
• A leaking blood vessel.
• Stroke.
• Puncture of the heart.
• Arrhythmias.
• Sudden death.

What To Think About

A pacemaker will be implanted to maintain normal heart rhythm after AV node ablation.

After AV node ablation, you will need to take anticoagulant medicines because you will still be at risk for stroke.

Heart problems: Should I have catheter ablation?

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References

Citations

1. Callahan TD IV, Natale A (2008). Catheter ablation of atrial fibrillation. Medical Clinics of North America, 92(1): 179–201.