Surgical Cardiac Ablation

(Also called: MAZE procedure, Concomitant surgical ablation)


During surgical cardiac ablation, small cuts are made in the heart tissue of the atria, the upper chambers of the heart. These cuts block the abnormal electrical pathways and restore the heart’s normal rhythm. Surgical cardiac ablation is recommended for patients whose AF is chronic and has not responded to treatment with drugs or other less invasive techniques.

Traditionally, the cuts (incisions) were made with a scalpel and sewn back together, which was difficult and risky. New incision technologies have reduced the risk and difficulty of the procedure. These technologies include:

  • Radio-frequency, which uses heat energy to make the incisions. This is the most common technology used for surgical cardiac ablation at the University of Ottawa Heart Institute.
  • Cryothermy, which uses extreme cold to freeze and kill small areas of heart tissue. This technology is also used for surgical cardiac ablation at the Heart Institute, especially when performing the full, minimally invasive MAZE procedure.
  • Microwave, laser, and ultrasound technology, all of which also use heat energy to make the incisions.

Surgical cardiac ablation may be performed as a stand-alone procedure, or it may be performed at the same time as open-heart surgery for another heart condition, such as coronary artery disease or valve disease. When it is performed at the same time as another procedure, it is called concomitant surgical ablation.


  1. You will have several tests done in the hospital before the procedure. These include: blood tests, an electrocardiogram, an angiogram, an echocardiogram, and in some cases a CT scan.
  2. A nurse or doctor will ask you to provide informed consent. A consent form must be signed before the procedure. Before signing, it is important to ask any additional questions you may have.
  3. You will be taken by stretcher to the Cardiac Operating Room.
  4. You will be given general anesthesia and will remain unconscious throughout the operation.
  5. A small incision is made in the right side of the chest in the case of a minimally invasive full MAZE procedure. A normal incision is made in the breastbone in cases of non-minimally invasive MAZE or concomitant surgical ablation. This allows the surgeon greater access to the heart.
  6. The heart’s blood vessels are connected to a heart-lung bypass machine, which pumps the patient’s blood through the body during the surgery.
  7. Once the heart-lung machine is pumping blood, the patient’s heart is temporarily stopped.
  8. A surgeon makes a series of cuts and burn or freeze lines in the muscle of the upper chambers of the heart that are responsible for the arrhythmia. These lines disrupt the abnormal electrical activity that has developed.
  9. Once the lines are made, the heart is restarted and all incisions are closed.
  10. You will stay in the Cardiac Surgery Intensive Care Unit (CSICU) for about a day.
  11. After a day, you will be moved to a regular hospital room. The average hospital stay after surgical cardiac ablation is four to seven days.

Full recovery after surgical cardiac ablation usually requires four to six weeks.

Patient instructions

Patients will usually take the same medications after the surgery as they did before the surgery. Most patients receive anticoagulant drugs to prevent blood clots for a short time after surgery, and some patients may receive new anti-arrhythmic drugs.

Patients will undergo 48-hour Holter monitoring twice in the first year following ablation, and once a year after that. This monitoring is done to make sure that the atrial fibrillation does not recur.