What Is a Maze Heart Procedure?

A woman standing outside suffering from heart pain

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A maze procedure is a type of cardiac ablation surgery for atrial fibrillation (aFib), a rapid, irregular heart rhythm that cannot be controlled by other treatments. Also known as the Cox maze procedure, the operation involves creating a maze-like pattern of scar tissue in the atrium (the upper chamber of the heart) through which chaotic electrical impulses from the upper chambers to the lower chambers (ventricles) of the heart can travel. Doing so can help correct the scattered electrical impulses and restore normal heart rhythms. It's almost never performed as a stand-alone procedure but rather is done only in conjunction with another heart surgery and when aFib is symptomatic.


The maze procedure is used to correct atrial fibrillation when anti-arrhythmia drugs or procedures such as cardioversion haven't worked. The technique was first developed by Dr. James Cox of Duke University Medical Center in the 1980s and gradually perfected into what is today known as the Cox maze III technique.

The Cox maze III is often described as a "cut-and-sew maze" because it involves large incisions to access the heart as part of open surgery.

Although less commonly used compared to catheter ablation (in which the interior of the heart is accessed through a vein or artery in the groin, neck, or arm), the maze technique offers higher cure rates and may be recommended if other heart surgeries, such as a coronary artery bypass or mitral valve repair, are needed.

In addition to normalizing the heart rate, the maze procedure can help prevent long-term complications associated with uncontrolled aFib such as stroke and heart failure.

The Cox maze III procedure is the gold standard for the surgical cure of aFib, but there are variations of the technique that cardiac surgeons may use:

  • Cox maze IV: Referred to as a "mini-maze," a minimally invasive technique reserved for people who don't need open surgery. Instead, a flexible camera and tube-like ablation equipment are fed through tiny cuts between the ribs. The scar tissue created with either cold (cryoablation) or electricity (radiofrequency ablation) destroys cells on the heart that cause aFib.
  • Convergent procedure: Similar to a mini-maze but accesses the inside and outside of the heart. For this procedure, tube-like ablation equipment is directed to the back wall of the left atrium through an incision in the abdomen. After scar tissue is generated using cryoablation or radiofrequency, a catheter is threaded inside the heart to destroy any remaining tissues that cause aFib.

Risks and Contraindications

When performed as part of open surgery, the Cox maze III procedure is associated with the same relative risks of any open-heart procedure. These include:

  • Chest wound infection
  • Breathing difficulties
  • Neuralgic chest pain
  • Arrhythmia (irregular heartbeat)
  • Blood loss
  • Blood clots
  • Edema (fluid overload)
  • Memory problems
  • Pneumonia
  • Respiratory failure
  • Kidney failure
  • Heart attack
  • Stroke

Because the Cox maze IV "mini-maze" and convergent procedure are less invasive, the risks are correspondingly less and may include:

  • Chest wound infection
  • Neurologic chest pain
  • Arrhythmia
  • Blood loss
  • Accidental perforation of the esophagus or lung

If used appropriately, the Cox maze IV can be just as effective as the Cox maze III with fewer risks and even more effective than catheter ablation.


Certain conditions contraindicate use of the maze procedure. These include a previous right thoracotomy, poor left ventricle ejection fraction (a sign of heart failure), and severe atherosclerosis ("hardening") of the aorta, iliac, or femoral blood vessels.

Before the Procedure

If your healthcare provider recommends you have a maze procedure, it is likely because you have another heart condition in addition to AFib that requires treatment. To assess whether you're a good candidate for surgery, you'll be sent for a pre-surgery evaluation involving a series of tests, including:

  • Blood tests
  • Complete physical exam
  • Computed tomography (CT)
  • Echocardiogram
  • Electrocardiogram (ECG)
  • Holter monitor
  • Nuclear stress test
  • Transesophageal echocardiography (TEE)


The maze procedure is performed on an inpatient basis. The amount of time you spend in the hospital will depend on whether you undergo open surgery or a mini-thoracotomy.

Even though the surgery will take between two and four hours, you may need to spend up to 10 days in the hospital, including a day or two in the cardiac intensive care unit (ICU).


The maze procedure is performed in the cardiac surgical unit of a hospital.

What to Wear

You can wear whatever you like to go to the hospital, as you will need to change into a hospital gown once you are in your room. Leave jewelry and other valuables at home: Your room may have a cabinet or bedside table that can be locked but hospitals typically will not take responsibility for lost or stolen property.

Food and Drink

As with other operations that require general anesthesia, you will need to arrive at the hospital with an empty stomach, which means fasting for eight to 12 hours beforehand. It's likely your procedure will take place in the morning.

You will also be asked to stop taking blood-thinning medications such as Coumadin (warfarin) or nonsteroidal anti-inflammatory drugs such as Advil (ibuprofen) prior to the procedure. To avoid interactions and surgical complications, make sure your surgeon knows about any drugs you take, whether they are prescription, over-the-counter, or recreational.

Cost and Insurance

The maze procedure is rarely an elective procedure and, as such, should be covered in part or in full by health insurance. If you do not have insurance, be aware the procedure can run into the tens of thousands for dollars, not including the cost of hospitalization and post-surgical care.

However, you may be able to negotiate an extended payment plan with the hospital or a discounted upfront cash payment with your specialists. You can explore strategies and discounts that may make the cost of surgery less burdensome with a hospital financial advisor.

What to Bring

You will need to bring some form of ID and your insurance card to be admitted to the hospital.

You will need enough clothing, medication, and self-care necessities to get through several days in the hospital. However, since you'll likely spend a day or two in the intensive care unit (ICU), it may make sense to pack a small bag to bring with you to hospital and a second larger one that a family member or friend can bring to you after you're transferred from the ICU to a regular hospital room.

You will also need to arrange for someone to drive you home when you're discharged.

During the Procedure

A cardiothoracic surgeon will oversee the maze procedure. Other members of the surgical team include the anesthesiologist and operating room nurses and technicians.

Because the maze procedure is generally performed alongside another heart surgery, there may be a perfusionist on hand to operate a heart-lung bypass machine if needed.


After you fill in the hospital registration forms, you will be accompanied to your room and given a hospital gown to change into.

You will then meet with a nurse or technician who will confirm you haven't eaten since midnight and will perform a series of preoperative tests (including blood tests, blood oxygen, and blood pressure) and place electrodes on your chest to monitor your heart rhythm on an ECG machine. An intravenous (IV) line will be placed in a vein, usually in the back of your hand or in your arm.

The anesthesiologist will then come in to discuss any allergies or previous complications you may have had with anesthesia. When the workup is complete and you're cleared for surgery, you will be wheeled into the operating room on a gurney where you'll receive general anesthesia to put you completely to sleep.

Throughout the Procedure

Once the anesthesia takes effect, you will be intubated (a tube will be inserted into your throat and a large airway of one lung) and connected to a ventilator to assist with breathing.

Since most maze procedures are performed as open surgeries, the operation will begin with a sternotomy in which an incision is made in the middle of your chest and your sternum (breastbone) is cut in two using a special saw, splitting the bone vertically so the surgeon has direct access to your heart.

You will then be hooked up to a heart-lung bypass machine which takes over the function of the heart, allowing the surgeon to operate on a still heart. Using the Cox maze III technique, the surgeon will access the right atrium and create a pattern of lines⁠ using either cryoablation or bipolar radiofrequency⁠ to block erratic electrical impulses and keep them moving through the heart.

Once all of the pathways have been scarred, your sternum will be closed using sterile surgical wire and the incision sutured. Chest tubes may be inserted to drain blood that may accumulate around the heart.


After the procedure, you will be transferred to a transitional room and then to the ICU where you will be monitored as you awaken naturally from anesthesia. It will take several hours for the anesthesia to fully wear off.

After the Procedure

Expect to spend one or more days in the ICU under the care of critical care nurses and an intensivist (ICU healthcare provider). During your recovery, your heart’s electrical activity will be closely monitored to determine if the procedure was successful.

Within 12 hours of surgery, once the anesthesia wears off and the breathing tube is removed, you will be helped to a chair. Sitting upright is a vital part of postoperative care as it helps prevent complications like blood clots and pneumonia.

There may also be temporary wires extending from the incision that can be connected to an external pacemaker in case of an emergency. (The surgeon may recommend the placement of a permanent pacemaker during the surgery to provide better control of your heart rhythm.)

After one to two days in intensive care, you will be transferred to a regular nursing unit. Thereafter, you can expect to spend anywhere from three to seven additional days in hospital depending on the complexity of the surgery and your response to postoperative care.

Cardiac rehabilitation will start while you are in the hospital and continue once you are returned home.


The Cox maze procedure is a highly successful treatment for atrial fibrillation with response rates exceeding 90%. With that said, recovery from open-heart surgery can take six to eight weeks and require intensive postoperative rehabilitation.

You will likely be placed on blood thinners and anti-arrhythmia drugs for a few months after the operation. Diuretics ("water pills") like Lasix (furosemide) may be prescribed to prevent fluid overload and reduce the risk of postoperative heart failure.

Roughly 60% of patients will experience skipped heartbeats or transient aFib in the weeks or months following a maze procedure due to swelling and inflammation of heart tissue. If these symptoms do not resolve on their own, a pacemaker may be required.


After you go home, you will have a follow-up appointment with your surgeon within a week and then another with your cardiologist within a month. You also are likely to need an ECG at three months, six months, and 12 months post-surgery, and once yearly thereafter.

A Word From Verywell

A maze procedure can seem scary, particularly since it usually accompanies major heart surgery. However, if atrial fibrillation is undermining your quality of life, you may find it encouraging to know that the procedure usually is highly effective.

If atrial fibrillation occurs on its own, you may benefit from an adjustment of your current medications or a less invasive procedure, such as cardiac ablation. Speak with your cardiologist about the most appropriate option and don't hesitate to seek a second opinion if you remain uncertain.

13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Jennifer Whitlock, RN, MSN, FN
Jennifer Whitlock, RN, MSN, FNP-C, is a board-certified family nurse practitioner. She has experience in primary care and hospital medicine.