Maze Procedure for Atrial Fibrillation

A maze procedure is a heart surgery that treats AFib, or atrial fibrillation. By creating a specific pattern (maze) of scar tissue, the procedure blocks abnormal signals but allows normal heartbeat signals to come through. The success rate for a maze procedure is 80 to 90%. Recovery can take a month or more.


A maze procedure creates a maze pattern to treat atrial fibrillation.
In a maze procedure, a surgeon makes a maze pattern on your heart tissue to treat atrial fibrillation.

What is a maze procedure?

A maze procedure or Cox-maze IV procedure is the creation of scar tissue in a maze pattern that blocks abnormal signals that cause atrial fibrillation, the most common abnormal heart rhythm. But a signal for a normal heart rhythm can still get through the maze, bringing your heart rhythm back to normal.

The maze your healthcare provider creates is similar to a maze game that has only one way in, one way out and one pathway between them. In addition to these, there are several routes that don’t lead anywhere. This type of pattern in both atria (upper heart chambers) stops abnormal signals from traveling, yet allows your atria to receive a normal signal.

Healthcare providers use cryoablation (freezing) or ablation with radiofrequency energy to injure tissue and make it form scar tissue. They can do this as a stand-alone procedure or at the same time as surgery for a different condition.

The Cox-maze IV procedure, the most recent version of the original maze procedure, is the gold standard surgery for atrial fibrillation.

Healthcare providers can do this procedure through a:

  • Sternotomy method (6- to 8-inch vertical cut down your sternum bone in your chest where your left and right ribs come together).
  • Thoracoscopic method (a cut between your ribs).


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Why is a maze procedure done?

A maze procedure returns your heart rhythm to normal.

This is an option for people with atrial fibrillation when:

  • Medicines don’t work or you can’t take them.
  • Blood clots (such as strokes) happen.
  • You’re already having surgery for another heart issue (like bypass or valve surgery) and you have atrial fibrillation as well.
  • Catheter ablation didn’t work.

What does a maze procedure treat?

A maze procedure treats atrial fibrillation (AF or AFib), which is the most common abnormal heart rhythm. Atrial fibrillation is an irregular, frequently rapid heart rhythm that starts in the atria (top chambers of your heart).

With a normal sinus rhythm, a single impulse travels in an orderly way through your heart. When you have atrial fibrillation, many impulses start at the same time and spread through your atria. This causes a fast and disorganized heartbeat.

Atrial fibrillation doubles the risk of death. It also increases the risk of stroke five to seven times compared to someone without atrial fibrillation. In addition, atrial fibrillation may cause congestive heart failure and uncomfortable symptoms from a rapid heart rate.

Maze surgery can:

  • Get your heart back to a normal rhythm.
  • Control your heart rate.
  • Prevent blood clots.
  • Reduce your risk of stroke.


Procedure Details

What happens before a maze procedure?

You’ll need a few tests and meetings before your procedure. You’ll:

  • Have a transthoracic echocardiogram to check left atrium size and check for diseased valves.
  • Have a chest CT (computed tomography). If you’re having a minimally invasive procedure, you may also need a CT scan of your abdomen and pelvis.
  • Get instructions on what you can eat and drink before surgery and what medications to take.
  • Meet with your anesthesiologist, cardiologist and surgeon.

What happens during a maze procedure?

Simplified maze procedure steps include:

Sternotomy method

  1. Cut down the middle of the sternum.
  2. Start cardiopulmonary bypass (machine to handle your heart and lung functions for you during surgery).
  3. Use ablation to isolate pulmonary veins so electrical signals don’t reach them.
  4. Use ablation to create scar tissue in a specific maze pattern in the right and left atria.
  5. Remove or close the left atrial appendage.

Thoracoscopic method

  1. Make a cut between ribs so you can put tools through it.
  2. Start cardiopulmonary bypass (for certain versions of the procedure).
  3. Deflate your lung to allow a minimally invasive procedure.
  4. Insert port and endoscope (tube with a camera) between specific ribs.
  5. Complete ablations similar to the sternotomy method.
  6. Remove or close the left atrial appendage.

Your healthcare provider will choose the method that’s best for you. Both methods use ablation to create a maze of scar tissue to correct atrial fibrillation. With the thoracoscopic (less invasive) type, you may have fewer complications and a shorter hospital stay.

Some people use the term “maze procedure” to mean any ablation procedure to treat atrial fibrillation. To be a true maze surgery, you need ablation on both atria, according to a standard technique. In some people, a more limited procedure (like pulmonary vein isolation) may be appropriate.

Left atrial appendage

When your provider does ablation on your left atrium, they will also cut off or close your left atrial appendage. This small, ear-shaped tissue flap is a common source of blood clots and strokes in people who have atrial fibrillation. Researchers believe 90% of clots start here in people with atrial fibrillation.

Blood can get stuck in this appendage and clots can form. A clot that breaks loose can get into your bloodstream and cause a stroke. Closing or removing your left atrial appendage reduces your risk of stroke.

Surgeons can use stitches, staples or a special device to close your left atrial appendage, not allowing blood to get to it. They do this for both surgical and minimally invasive maze procedures.


What happens after a maze procedure?

You’ll be in an intensive care unit (ICU) for one or two days after surgery. Then you’ll move to a regular hospital room for a few more days, depending on what other procedures you had. People who’ve had the minimally invasive surgery leave the hospital four days after their procedure. Others may need a week.

You may need to take medicine after your maze procedure, such as:

  • Anticoagulants (blood thinners) like warfarin (Coumadin® or Jantoven®) or apixaban for at least three months to prevent blood clots. After this time, your cardiologist will determine whether you need to continue anticoagulation.
  • Medicine to control abnormal heartbeats.
  • Diuretics to reduce how much fluid your body retains.

Sometimes, people who have a maze procedure will still need additional catheter ablations to completely eliminate atrial fibrillation. It’s important that people who have a maze procedure continue to follow up closely with their cardiologist to determine the need for an additional ablation.

Risks / Benefits

What are the advantages of a maze procedure?

Advantages of a maze surgery include:

  • A success rate of 80 to 90%.
  • Long-term relief for atrial fibrillation.
  • A lot fewer blood clots and lower risk of stroke.

What are the risks or complications of a maze procedure?

About 30% to 50% of people have skipped heartbeats or short episodes of atrial fibrillation during the first three months after maze surgery. This happens because your atrial tissue gets swollen. Medicines help with these issues. Once your heart heals, abnormal heartbeats should go away.

About 6% of people who have a surgical maze procedure need a pacemaker after surgery because of a rhythm problem that wasn’t found before, such as:

Recovery and Outlook

What is the maze procedure recovery time?

It takes about three to six weeks to get back to your normal activities. Maze surgery recovery is faster with the minimally invasive method because you don’t have a large incision in your chest.

When To Call the Doctor

When should I see my healthcare provider?

You should contact your cardiologist if you have atrial fibrillation symptoms after your surgical maze procedure.

You’ll have follow-up appointments or tests at certain times, such as:

  • Healthcare provider appointment one week after leaving the hospital.
  • Cardiologist appointment about a month after leaving the hospital.
  • Electrocardiogram (EKG) three, six and 12 months after surgery and then once a year.
  • Holter monitor six and 12 months after surgery.

Additional Common Questions

What is a maze III procedure?

This is the third version of the maze procedure that heart surgeons have used since its invention. The most current version of this procedure is the Cox-maze IV procedure, which uses ablation instead of cuts and stitches to make the maze.

What is the difference between ablation and a maze procedure (ablation vs. maze procedure)?

In the past, a maze procedure used cuts and stitches to create scar tissue. Now, the maze procedure uses ablation. The use of ablation doesn’t automatically make it a maze procedure. A maze procedure treats both the left and right atria and creates a specific maze pattern.

How long does a maze procedure take?

When you’re having heart surgery for a different issue, your healthcare provider will need about 15 to 30 more minutes to do the maze procedure.

What does maze procedure stand for?

Maze procedure isn’t short for anything. It refers to the maze-like pattern of scar tissue you get on your heart during a cardiac maze procedure.

A note from Cleveland Clinic

If you have atrial fibrillation or AFib, a maze procedure can give you relief. It’s important to talk with your healthcare provider about why you may or may not be a candidate for the minimally invasive version of a cardiac maze procedure. Follow your provider’s instructions when caring for yourself after surgery. That means taking all prescribed medications and going to all follow-up appointments. Be sure to ask your provider any questions you have.

Medically Reviewed

Last reviewed on 04/06/2022.

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