Maze procedure

The maze procedure is a treatment for an irregular heartbeat called atrial fibrillation (AFib). A surgeon uses heat energy, cold energy or a scalpel to create a pattern of scar tissue in the heart's upper chambers. The pattern is called a maze. Scar tissue in the maze can block the faulty electrical heart signals that cause AFib.

Why it's done

The maze procedure is done to treat atrial fibrillation (AFib), a type of irregular heartbeat. An irregular heartbeat also is called an arrhythmia. Your healthcare team may suggest the maze procedure if you have AFib that doesn't get better with medicines or other treatments.

Risks

Some risks of the maze procedure are:

  • Bleeding or infection where the surgical cut is made.
  • A new irregular heartbeat or one that gets worse.
  • Need for a small device called a pacemaker, which keeps the heart from beating too slowly.
  • Blood clots.
  • Stroke.

Ask your healthcare professional to talk with you about all the possible risks and benefits of the treatment.

What you can expect

You first get tests that check your heart health. The tests help your healthcare team find out if the maze procedure can help you.

During

The maze procedure most often is done with medicines that put you in a sleeplike state. This is called general anesthesia.

During the maze procedure, a surgeon creates specific lines in the heart using one or more of the following:

  • A sharp tool called a scalpel.
  • Heat energy, also called radiofrequency energy.
  • Cold energy, also called cryothermal energy.

The pattern of lines created is called a maze. It scars over time. The scar tissue blocks or redirects the faulty heart signals that cause irregular heartbeats.

There are various ways to reach the heart to do the maze procedure.

Surgical maze

This is a type of heart surgery. You are put on a heart-lung machine. The machine keeps blood and oxygen flowing through your body.

Another name for surgical maze is the Cox-maze procedure. It's the preferred AFib treatment in those who need another heart surgery, such as heart valve surgery.

Surgical maze may be done in two ways:

  • Open-heart surgery. The surgeon makes a long cut in the chest through the breastbone to reach the heart. This is called a sternotomy. Then the surgeon uses a scalpel, heat energy or cold energy to create the maze.
  • Minimally invasive robotic surgery. Very small cuts and robotic technology are used to reach the heart. With this method, only heat energy or cold energy is used to create the maze pattern.

Surgeons can do other heart treatments or place a pacemaker, if needed, during the surgical maze procedure.

Catheter ablation maze

This treatment uses thin, flexible tubes called catheters. The surgeon makes a cut to reach a blood vessel, usually in the groin area. The catheters go into the blood vessel. Then, they are moved to the correct area in the heart. Sensors on the end of the catheters give off heat or cold energy. The energy helps create a pattern of scar tissue that blocks or redirects the faulty heart signals.

Mini-maze

Sometimes both surgery and catheter methods are used to create the maze. This is called a mini-maze procedure or a hybrid approach.

Results

Most people who have atrial fibrillation (AFib) have a better quality of life after the maze procedure. But there's a chance the irregular heartbeat will come back. If this happens to you, you might need medicine or another maze procedure.

If your heartbeat becomes too slow after the maze procedure, your healthcare team might suggest a pacemaker.

April 09, 2024
  1. Lee R. Atrial fibrillation: Surgical ablation. https://www.uptodate.com/contents/search. Accessed Oct. 20, 2025.
  2. Ferri FF. Atrial fibrillation. In: Ferri's Clinical Advisor 2026. Elsevier; 2026. https://www.clinicalkey.com. Accessed Oct. 20, 2025.
  3. Wyler von Ballmoos MC, et al. The Society of Thoracic Surgeons 2023 clinical practice guidelines for the surgical treatment of atrial fibrillation. The Annals of Thoracic Surgery. 2024; doi:10.1016/j.athoracsur.2024.01.007.
  4. Catheter Ablation. UpBeat.org. https://upbeat.org/common-treatments/catheter-ablation. Accessed Oct. 20, 2025.
  5. Libby P, et al., eds. Atrial fibrillation: Clinical features, mechanisms, and management. In: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 12th ed. Elsevier; 2022. https://www.clinicalkey.com. Accessed Oct. 20, 2025.
  6. McGilvray MMO, et al. Efficacy of the stand-alone Cox-Maze IV procedure in patients with longstanding persistent atrial fibrillation. Journal of Cardiovascular Electrophysiology. 2021; doi:10.1111/jce.15113.
  7. Kaba RA, et al. A chronicle of hybrid atrial fibrillation ablation therapy: From Cox maze to convergent. Arrhythmia and Electrophysiology Review. 2022; doi:10.15420/aer.2022.05.
  8. Medical review (expert opinion). Mayo Clinic. Oct. 30, 2023.
  9. Pang N, et al. Comparison of the different anesthesia strategies for atrial fibrillation catheter ablation: A systematic review and meta-analysis. Cardiology Research and Practice. 2022; doi: 10.1155/2022/1124372.

Atrial fibrillation ablation