2019 AF Symposium: Live! Convergent Hybrid Ablation for Atrial Fibrillation

by Steve S. Ryan

Convergent surgical lesions pattern

Background: The Convergent Hybrid Ablation is currently used for patients with persistent and longstanding persistent atrial fibrillation.

The Hybrid is performed under general anesthesia. First the surgeon accesses the outside (epicardial) of the heart and creates lesions on the posterior left atrial wall and around the pulmonary veins (PVs).

Next, the EP performs a standard PV catheter ablation from inside (endocardial) the heart, uses mapping systems to detect any gaps in the surgical ablation lines, and completes the surgeon’s lesion set, if needed.

Live Case from Atlanta: Sequential Endocardial and Epicardial Operation/Procedure

Symposium attendees got to watch a Convergent Hybrid operation/procedure performed Live from Emory Heart and Vascular Center at Saint Joseph’s Hospital, Atlanta, GA. Presenting doctors were cardiothoracic surgeon Dr. Michael Halkos and cardiac electrophysiologists (EPs) Dr. David DeLurgio and Dr. Kevin Makati.

Patient Description: a Difficult Case

The patient was a 62-year-old man who had been in A-Fib for 21 years, 10 years of which were in persistent A-Fib. He was also very tall. He also complained of being very fatigued.

They didn’t know the amount of fibrosis the patient had developed. (One would think someone in A-Fib for such a long time would have developed a significant amount of fibrosis.) They did not measure the patient’s amount or type of fibrosis. They mentioned that they hoped the fibrosis was localized rather than diffuse and that the patient did not have a Utah 4 or a Strawberry-type large fibrosis area. (About Utah and fibrosis, see High Fibrosis at Greater Risk of Stroke and Precludes Catheter Ablation)

The patient had been on rate control drugs and the antiarrhythmic Sotalol. It was not mentioned if anyone had ever tried a normal catheter ablation on this patient before going to the Convergent operation/procedure.

Surgery on Outside of Heart

In this version of the hybrid, the cardiothoracic surgeon accesses the outside posterior of the heart through the subxiphoid process cutting through the central tendon of the soft tissue of the diaphragm making a 2-3 cm incision. The surgeon achieves direct vision of the posterior cardiac structure with a miniature camera (from EnSight by AtriCure). (The xiphoid process is a cartilaginous section at the lower end of the sternum.)

Size comparison: Atricure EPI-Sense device size vs. ablation catheter

Convergent Catheter vs. PVI Ablation Catheter: The catheter used to make the burns in the Convergent operation is unlike a standard point-by-point RF catheter with force sensing.

The Atricure EPi-Sense Guided Coagulation System with VisiTrax® technology: How it works.

Instead it is a long linear catheter with multiple RF coils on its side which is placed horizontally to make long, large burns on the heart.(AtriCure EPi Sense Coagulation Device).

The burns are normally 90 seconds long at 30 watts. This catheter can also be used for pacing, sensing, and to produce electrograms. Impedance drops (10%) are used to verify lesion effectiveness. The catheter has a notch on the top which can be used to orient the catheter.

Phase I: Live Surgical Operation

When starting, the Symposium audience watched as the surgeon, Dr. Michael Halkos, accessed the outside of the heart through the diaphram. Then he identified the left inferior and right inferior PVs.

Illustration of surgical lesions to outside of heart

Using these benchmark structures, he then started to ablate the whole of the posterior left atrium including any other areas of the posterior left atrium he could access.

The burns can overlap and can be repeated. (We only saw them make 2 burns, but usually 20 to 40 burns are made.)

We also saw the surgeon use a suction catheter to remove any blood and liquid from the area being worked on. Note: The pericardium sac is filled with saline to help prevent damage to the esophagus.

Phase II: EP Procedure

Because of time constraints, we didn’t get to see Dr. David DeLurgio, the cardiac electrophysiologist (EP) work on this patient after he was wheeled into the EP lab.

Dr. DeLurgio was scheduled after the surgery phase to later perform a PVI ablation and ablate the right atrium Cavo-tricuspid Isthmus (CTI) to prevent Flutter.

His tasks would also include using mapping technology to check the surgeon’s lesions and fill in any gaps.

Editor’s Comments

Who should consider a Hybrid Ablation for Atrial Fibrillation? Patients with persistent and/or longstanding persistent atrial fibrillation. Specifically, the Hybrid Surgery/Ablation might be an effective option for:

• highly symptomatic patients with persistent atrial fibrillation and longstanding persistent atrial fibrillation who have failed one or two catheter ablations,
• for someone with a significantly enlarged left atrium, or
• for someone who is morbidly obese (making it difficult to create imaging maps necessary for catheter ablations).

This 62-year-old Patient:  It was not mentioned if anyone had ever tried a normal catheter ablation on this patient before going to the Convergent operation/procedure.

I hope for this 62-year-old male patient that he was treated first with a less invasive PV catheter ablation (or two). If the ablation(s) failed, only then would his doctors recommend the much more invasive and riskier convergent surgery.

This was a “sequential” Hybrid approach. There is also a “non-synchronous” or two-staged version where the surgeon and the EP work on the same patient but at different times and/or places.

“Minimally invasive”: Though called “minimally invasive,” the Convergent operation is still major heart surgery. It’s invasive, traumatic, complicated, requires considerable surgical skills and experience, and is potentially risky.

My Bias: Please be advised that I am personally biased against the Convergent Hybrid operation/procedure. Whenever I see it, I get nauseous and sick to my stomach watching them burn the whole of the posterior left atrium wall. To me this is overkill.

The outside posterior left atrium is turned into dead, fibrotic tissue. There is no more blood flow, transport and contraction function no longer work, nerve transmission is destroyed, normal heart muscle fibers turn into non-contracting scar tissue. The ability of the left atrium to contract risks being hindered.

The surgeon does tremendous damage to the outside posterior left atrium which can never be restored. This may weaken the heart and contribute later to heart problems like congestive heart failure.

I can’t imagine having my outside posterior left atrium wall destroyed like that. All too many patients today suffer from weak hearts due to heart muscle damage.

Difference between Surgeons and EPs: Cardiac Electrophysiologists (EPs) do often ablate in the inside posterior left atrium such as by creating a box lesion set. But they try to do as little permanent damage to the heart as possible.

Similar ablation techniques are called ‘hybrid ablation technique’, ‘convergence process’, ‘Convergent Maze Procedure’ and ‘Convergent Ablation”’

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Whereas surgeons in the Convergent operation try to do as much damage as possible. Their goal is durable posterior wall isolation.

My concern: Is it really necessary to completely obliterate the outside left atrium posterior wall to make a patient A-Fib free? Perhaps. In some patients this may indeed be necessary. But is this necessary in every patient having a convergent operation?

For more about the Hybrid approach, see my article: Advantages of the Convergent Procedure and the VIDEO: The Hybrid Maze/Ablation for Atrial Fibrillation for Persistent A-Fib Includes animation and on-camera interviews. Published by Tenet Heart & Vascular Network. Length 4:30

If you find any errors on this page, email us. Y Last updated: Friday, April 2, 2021

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