The AFib-Surgery Intersection
Approximately 30–40% of patients undergoing cardiac surgery have pre-existing atrial fibrillation. When you already need surgery for a valve or coronary problem, the question arises: should we also treat the AFib while we are there?
The answer depends on your AFib pattern, left atrial size, symptom burden, and what the primary surgery involves.
What Is the Maze Procedure?
The Cox-Maze IV procedure creates a specific pattern of lesions (scar lines) in the atrial tissue using radiofrequency ablation or cryoablation. These scar lines block the chaotic electrical signals that cause AFib, forcing electrical impulses to follow a single organized path — hence the name "maze."
When performed concomitantly (at the same time as another cardiac surgery), the Maze procedure adds approximately 15–30 minutes to the operation.
Success Rates and Evidence
The evidence supporting concomitant Maze is strong:
- Freedom from AFib at 1 year: 70–90% with Maze vs. 20–40% without
- Stroke reduction: Patients in sinus rhythm after Maze have significantly lower long-term stroke risk
- Anticoagulation discontinuation: Many patients can stop warfarin/DOACs if they maintain sinus rhythm
- Quality of life: Consistent improvements in exercise tolerance and symptom scores
The 2023 ACC/AHA guidelines give a Class I recommendation for surgical ablation of AFib in patients undergoing concomitant cardiac surgery — meaning the evidence strongly supports doing it.
When It Makes Sense to Add the Maze
The best candidates for concomitant Maze are patients who:
- Have persistent or long-standing persistent AFib (not just a single episode)
- Are already undergoing mitral valve surgery (the left atrium is already exposed)
- Have a left atrial diameter <5.5–6.0 cm (larger atria have lower success rates)
- Are symptomatic from AFib (palpitations, fatigue, exercise intolerance)
- Wish to discontinue anticoagulation if possible
When to Think Twice
Adding the Maze may not be ideal when:
- The left atrium is massively dilated (>6.5 cm) — success rates drop below 50%
- The primary surgery is high-risk and adding time could increase complications
- AFib has been present for >10 years with significant atrial fibrosis
- The patient has paroxysmal AFib that is well-controlled with medications
Left Atrial Appendage Management
Regardless of whether a full Maze is performed, patients with AFib undergoing cardiac surgery should have the left atrial appendage (LAA) excluded or excised. The LAA is the source of >90% of stroke-causing clots in AFib patients. Surgical exclusion can be performed with clips, staples, or excision with minimal added risk.
The Second Opinion Advantage
Not all surgeons are experienced with the Maze procedure. If you have AFib and are facing cardiac surgery but the Maze was not discussed, it is worth asking why. A WhiteGloveMD second opinion evaluates your complete clinical picture — including your AFib burden, atrial anatomy, and primary surgical indication — to ensure no opportunity for rhythm restoration is missed.