Surgical Ablation for Atrial Fibrillation

Learning about Surgical Treatments for Atrial fibrillation
An educational brochure describing the surgical treatment of atrial fibrillation.
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Tratamiento Quirúrgico de la fibrilación auricular
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Surgical ablation for atrial fibrillation is investigational and has not been approved for treatment by the US Food and Drug Administration.

Surgical Ablation Procedures

Surgical ablation may be performed on either an arrested or beating heart, in an open-heart procedure, or in a minimally invasive closed-chest procedure. In an open-heart procedure, surgical ablation can be performed as a lone procedure or concomitantly with mitral valve replacement/repair or other specified procedures.

An Evolution of the Cox-Maze III Procedure

Although the Cox-Maze III boasts a high success rate, it is a time consuming, technically difficult procedure. Because of this, surgeons have been working to improve upon the ease of the procedure by using energy sources instead of incisions to create lines of ablation on the atria.

Ablation energy sources can be organized into two major groups:

Unipolar

Bipolar
Cryothermy Dry Bipolar Radiofrequency
High Intensity Focused Ultrasound Irrigated Bipolar Radiofrequency
Irrigated Unipolar Radiofrequency  
Microwave  
Unipolar Radiofrequency  
 

Unipolar energy sources radiate either energy or cold from a single source. None of the unipolar devices provide the surgeon with an indication of when the ablation results in a transmural lesion. On the other hand, bipolar RF ablation has the ability to overcome these shortcomings by creating reliable and rapid transmural lesions.76

In April 2006, at the annual meeting of the American Association for Thoracic Surgery (AATS), research evidence was presented showing that ablation techniques reduced the time required for the Cox Maze III surgery without compromising the outcome of the surgical procedure. This resulted in over 90% of patients from both surgical groups being free of atrial fibrillation recurrence after one year.66

Cox-Maze IV 

The Maze Ablation Procedure (or Cox-Maze IV) is an open-heart procedure that often requires a heart-lung bypass. Surgeons use an energy source to create uniform lesion sets of transmural ablation along the faulty electrical sites in the heart. This creates conduction block. In order to make the lesion sets, a clamp is closed around the targeted tissue, and energy is delivered to the tissue. Some systems include a mechanism to assess the transmurality of the ablation lines to confirm conduction block.

Lesions are made along the left and right atria based on the classification of atrial fibrillation affecting the heart and at the surgeon’s discretion. The left atrial appendage is excluded or excised to reduce the risk of thromboembolism, and is considered a mandatory practice by The Society of Thoracic Surgeons (STS).68

 

 Cox-Maze IV Risks

Risks involved in the Cox-Maze IV procedure are often related to the energy source and the surgical ablation method. Unipolar radiofrequency energy sources have been shown to cause esophageal perforation in 1% of patients receiving an open heart Cox-Maze IV procedure.71 In 2000, a study performed at the Mayo Clinic involving 221 patients reported a mortality rate of 1.4%.72 Other complications include bleeding, which may require a second procedure, and abdominal ischemia.73 Reduction in the number of lesions used in the Cox-Maze IV procedure increases the risk of the occurrence of atrial flutter.74 "Overflow" of energy during surgical ablation has been the cause of tissue stenosis and contracture that can lead to varying degrees of damage.74

Open-Heart Surgical Ablation Success Rates 

In 2004, research results from the Division of Cardiothoracic Surgery at Washington University School of Medicine in St. Louis reported that 91% of patients who received open heart surgical ablation procedures using a bipolar radiofrequency ablation system were free from atrial fibrillation at 6 months, with only 10 out of 40 patients requiring antiarrhythmic therapy.44

According to the 2007 HRS consensus statement, all patients with AF undergoing other cardiac surgery should be considered for AF ablation if the risk of adding the procedure is low, there is a reasonable chance for success, and the surgery is performed by an experienced surgeon.76

Participate In a Surgical Ablation Clinical Trial

Your doctor can help you decide what your treatment options are based upon the type of atrial fibrillation you have and your overall health and medical history. Take the time to educate yourself about your treatment options, write down questions to ask your doctor at your next follow-up, and speak to your physician about your options and concerns. If you are a patient or physician and are interested in learning additional information about clinical studies currently underway, please visit clinicaltrials.gov.