Patients with an arrhythmia called atrial fibrillation (also called AFib) have a problem with the electrical signal that makes the heart pump.

The signal travels erratically through the heart muscle, causing the upper chambers (atria) to quiver instead of contract.

When medications or mild electrical shocks (cardioversion) fail to stop the problem, our doctors may recommend an operation to straighten the electrical pathway.

Some centers still do that by making tiny cuts in the heart, an approach known as the maze procedure. But we offer a much less invasive approach called CryoMaze, using heat or extreme cold.

CryoMaze Ablation at the University of Maryland

At the University of Maryland Heart and Vascular Center, we offer an update to the maze procedure for atrial fibrillation: substituting extreme cold (cryotherapy) for surgical cuts.

For some patients we can do this with a minimally invasive approach. At times, we can also combine the operation with another treatment called catheter ablation for a hybrid procedure. This relies on a close partnership between our specialized cardiologists and our heart surgeons.

How CryoMaze Works

In the past, heart surgeons could treat atrial fibrillation by making small cuts in the heart, then stitching them up. This allowed the heart to continue functioning, while creating scars that formed an appropriate electrical route — a pathway resembling a maze.

Instead, our surgeons create similar scars with a special probe that kills abnormal cells with extreme cold (cryotherapy). They can do that through two possible approaches:

  • Standard: Our surgeons go through the ribs on one side of the chest. This approach is more painful immediately after the operation but provides a faster recovery.
  • Minimally invasive: Our surgeons use cameras and make smaller incisions, on either the right or left side of the chest. A heart-lung machine is still needed, though.

CryoMaze Ablation vs. Catheter Ablation

In addition to CryoMaze, our doctors may recommend treating more severe arrhythmias with a related, minimally invasive approach called catheter ablation: the use of thin tubes and heat or severe cold to destroy abnormal heart cells.

Often, our team considers catheter ablation first. A recommendation for CryoMaze may come for one of two reasons:

  • Catheter ablation does not completely stop atrial fibrillation, so the team turns to CryoMaze.
  • The team already plans to do open-heart surgery for a different heart condition and can easily add a CryoMaze procedure. For example, a third of patients receiving a mitral valve repair also suffer from atrial fibrillation. (Learn more about mitral valve repair)

But patients can also choose to proceed directly to cryotherapy, with several advantages:

  • While catheter ablation is the best treatment for some atrial fibrillations, other patients can benefit more from CryoMaze.
  • CryoMaze is more invasive but can provide better first time results (75 to 80 percent success rate). Patients may need to repeat catheter ablation.
  • CryoMaze can create more scars to block erratic signals in the same amount of time.
  • If any electrical leaking remains, our specialized cardiologists can map the problem and touch up incomplete scars with catheter ablation.

Learn more about catheter ablation.

Hybrid Ablation

Sometimes the best approach for ablating atrial fibrillation is a hybrid procedure. This involves two parts:

  1. Heart surgeons start by performing CryoMaze ablation on the outside of the heart.
  2. Cardiologists finish by using catheter ablation on the inside of the heart. This completes the scars started by the surgeons and ensures the creation of a proper electrical pathway.

Using a hybrid approach instead of a full CryoMaze allows the team to avoid using a heart-lung machine, which temporarily takes over the function of the heart and lungs.