Washington University School of Medicine
The following is a description of different procedures that are presently
being used for the surgical treatment of atrial fibrillation.
I have written this in an attempt to clear up what has become a very confusing situation for
both patients and doctors. Initially, there was only one operation for
atrial fibrillation, which has been termed either the Maze procedure or the
Cox-Maze procedure in honor of Dr. James Cox who developed this operation.
The final iteration of the Maze procedure has been termed the Cox-Maze III.
Recently, the literature has been very confused by surgeons employing the
term “mini-Maze” to describe a wide variety of different, often ineffective,
surgery procedures. Most of these operations remain unproven at the present
time, and would be considered experimental. I will attempt to describe the
operations in layman’s terms.
(For another set of descriptions describing Maze and Mini-Maze labels and procedures, click here.)
1.The Maze procedure, the Cox-Maze procedure, the Cox-Maze III
procedure:
This operation involves making a myriad of different incisions on both the
left and right atria. It was developed in the mid-1980’s and first performed
in 1987. It was designed to prevent the electrical circuits that maintain
atrial fibrillation. There are now an over two decades of experience with this
operation. The results at Washington University in this population have
revealed a 98% 10-year cure rate. (Damiano, et al J Thorac Cardiovasc Surg 2003;126:2016-2021)
2.The Cox-Maze IV procedure:
This is a term that we have coined at Washington University to describe the
operation in which you perform the entire lesion set of the original Maze
procedure, but use ablation technology to replace the most of the incisions
of the operation. Various different energy sources have been used with
varying degrees of success. These include unipolar radiofrequency, bipolar
radiofrequency energy, microwave energy, and cryoablation. We have performed
this operation on over 130 patients at Washington University, and our one-
year cure rate is 92%. When we have matched these patients with similar
patients undergoing the cut-and-sew Cox-Maze III, our results have been
identical. (Gaynor, et. al J Thorac Cardiovasc Surg 2004; 128:535-542)
3.A modified Maze procedure:
This is a term used to describe a wide variety of operations in which the surgeon
chooses to perform just some of the Maze lesions. This usually involves just performing the left atrial lesions. This is done because the left atrium is responsible for most of the triggers which initiate atrial fibrillation. Some people will use the term “left atrial Maze” to describe these limited lesion sets.
The success rates of these operations have varied from 25% to 95%. It has
depended on the number of ablations performed, the technology, the energy
source used, and whether or not a biatrial versus a left atrial approach only
has been chosen. I would ask your surgeon to provide a detailed description
of his own result.
Two large multi-center reviews of results have revealed that biatrial approaches
appear to have a higher success rate than simply performing ablation on the left
atrium itself.
4.Mini-Maze
This also is a term used to describe a wide different types of procedures.
It is very confusing. Most surgeons use the term “Mini-Maze” to refer to
pulmonary vein isolation alone. This has been done principally with either microwave energy devices or bipolar radiofrequency clamps.
There has been no large published series with [surgical] pulmonary vein isolation. The early results appear to be mixed. There are some centers who have reported anecdotal good results, but have not subjected these to peer-reviewed publication. This is the way that we use in surgery to verify the accuracy of peoples’ individual reporting. In a peer-reviewed publication, your surgical results are objectively reviewed by other surgeons outside your institution, and then published for widespread dissemination.
It is fair to say that these procedures are experimental, but in some patients offer a
smaller-incision approach. There have been no studies documenting whether these types
of mini-procedures offer decreased complication rates after surgery for atrial fibrillation than a full Maze procedure, but they can avoid cardiopulmonary bypass.
The results with pulmonary vein isolation have generally been poor in people
with organic heart disease, particularly in patients with mitral valve
disease. There has been one report of good results in patients with lone
atrial fibrillation and no other heart disease. However, not all centers
have been able to duplicate these results. Our own results with pulmonar
vein isolation have yielded much lower success rates than the full lesion
set.