Mini Maze Procedure Success Rates

Reported results for minimally invasive surgical ablation procedures have varied from center to center. That likely reflects differing patient populations treated, energy sources and ablation devices used, and ablation techniques. In general, more experienced surgeons have better results. Thus, it’s crucial to find out how many minimally invasive afib procedures your surgeon has done.

Procedure success rates are typically in the 75%-90% range for paroxysmal atrial fibrillation and in the 50%-75% range for persistent afib. Newer lesions sets are producing better results, especially for persistent and longstanding persistent afib.

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Most published studies on minimally invasive afib surgery are based on an individual center’s experience. Most have used a bipolar radiofrequency clamp. Unipolar radiofrequency energy and cryothermy are used in many centers, but very little published data exists.

Recent minimally invasive surgical ablation publications include:

  • In one study, a bipolar radiofrequency clamp was used to treat 52 patients with paroxysmal atrial fibrillation. Patients received pulmonary vein isolation, ablation of the ganglionated plexi, and removal of the left atrial appendage (LAA). After ablation, the surgeon confirmed that conduction block had been achieved. The one-year freedom from afib rate was 80.8%, although some patients remained on antiarrhythmic medication. There were no instances of death, stroke, major bleeding, or phrenic nerve injury. Three patients who had Sick Sinus Syndrome (where the heart’s natural pacemaker, the sinus node, no longer works properly) needed to have a pacemaker implanted.1
  • A bipolar radiofrequency clamp was used by four centers participating in STAR (Surgical Treatment of Atrial Arrhythmias Registry). Of 118 patients who had minimally invasive afib surgery, 68% had paroxysmal afib. All patients had pulmonary vein isolation, but conduction block was not confirmed for all. Nearly 95% of patients had the left atrial appendage removed. Complications included collapsed lung in seven patients, acute lung injury in five, phrenic nerve injury in one, and permanent pacemaker implantation in three. There were no deaths or strokes. The success rate, defined as freedom from afib and antiarrhythmic drugs, was 80% for all patients at the last clinical follow-up.2
  • A unipolar radiofrequency probe was used to treat 104 patients with paroxysmal and persistent afib. The authors reported a 96% freedom from afib rate for paroxysmal afib patients and an 80% success rate for persistent afib. However, it’s unclear how many patients needed antiarrhythmic medications to remain afib-free. In terms of complications, one patient was converted to an open-chest procedure due to a rupture during left atrial appendage removal. Another had a transient ischemic attack. About 20% of patients had electrical cardioversion before discharge from the hospital.3
  • A totally thoracoscopic procedure using a bipolar radiofrequency clamp was used to treat 60 patients with paroxysmal afib, 32 patients with persistent afib, and 22 with longstanding persistent afib. At six months, 86.7% of paroxysmal patients were free of afib, and 71.7% were also off antiarrhythmic medications. The success rates were lower for patients with more severe forms of atrial fibrillation. About 50% of persistent patients were free of afib and off antiarrhythmic medications, as were 32% of patients with longstanding persistent afib. Complications included transient nerve injury (2 patients), renal failure (2 patients), pulmonary problems (5 patients), and inflammation of the cardiac tissue (1 patient).4
  • The Five-Box Thoracopscopic Maze Procedure also uses bipolar radiofrequency energy to treat patients in a minimally invasive approach. This technique has shown high success rates for treating patients with persistent and longstanding persistent afib. In the published results, only 19 patients with persistent afib had reached a six-month follow-up. All patients were afib-free and had discontinued antiarrhythmic medications. Complications included injury to the right pulmonary artery (1 patient) and implantation of a permanent pacemaker (1 patient).5 Data on additional patients treated with the Five-Box Thoracopsopic Maze Procedure were presented at the Society of Thoracic Surgeons meeting in January 2011. At that time, 179 patients had been treated, with 171 having had longstanding persistent afib. At six-month follow-up, 97% were free of atrial fibrillation and off antiarrhythmic drugs.6

In the FAST study (Atrial Fibrillation Catheter Ablation versus Surgical Ablation Treatment: A MultiCenter Randomized Clinical Trial), patients who had minimally invasive afib surgery after a failed catheter ablation had a much higher success rate than those who had another catheter ablation. Specifically, 65.6% of patients who had minimally invasive afib surgery were free of afib, flutter, and antiarrhythmic drugs after 12 months. This compared to only 36.5% of patients randomized to the catheter ablation treatment group.7 Therefore, if you’ve had a failed catheter ablation, you may wish to consider a minimally invasive afib procedure as an option.

Learn about Mini Maze Procedure Risks.

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