AF Symposium 2020

Live Case: Convergent AF Ablation

by Steve S. Ryan

Background: The Convergent Ablation is currently used for patients with persistent and longstanding persistent atrial fibrillation. It combines the efforts of a surgeon and an electrophysiologist (EP).

First, the surgeon accesses the outside (epicardial) of the heart to create lesions on the posterior left atrial wall and around the pulmonary veins (PVs). Second, the EP performs a PV catheter ablation from inside (endocardial) the heart, then maps the surgeon’s surgical ablation lines for any gaps, and if needed the EP completes the surgeon’s lesion set.

Live Via Streaming Video from Tampa, FL

Andrew Makati, MD

Andrew Sherman, MD

Drs. Andrew Makati (Electrophysiologist) and Andrew Sherman (Surgeon) from St. Joseph’s Hospital, Tampa, FL presented a live case of “Convergent AF Ablation―Staged PVI After Surgical Posterior Wall Isolation”.

The on-site moderator was Dr. Felix Yang from Maimonides Medical Center in Brooklyn, NY.

Patient with a Difficult Persistent Case

The patient they were working on was a 72-year-old male with persistent A-Fib/Flutter for 11 years. Previously he had a Cryo Ablation and many Cardioversions. He had tried the antiarrhythmic drug, amiodarone. His left atrial dimension was 5.1 (a normal left atrium measures around 2.0-4.0 cm).

Phase 1: Thoracoscopic Surgery

Video-assisted thoracic surgery (VATS) uses a tiny camera and surgical instruments inserted into your chest through one or more small incisions in your chest wall.

Surgeon Andrew Sherman began by showing slides of a thoracoscopic (through the chest) epicardial operation he had performed earlier in the week on another patient (Phase 1 of the Convergent operation).

He stated that the surgery has now turned more to a subxiphoid approach (the xiphoid is the lowest point of the breastbone). He stated that this surgery is “minimally invasive.”

(Called minimally invasive, video-assisted thoracic surgery uses very small incisions to access the inside of the chest cavity. But to the average patient, the Convergent operation is major surgery with all the potential complications and risks of heart surgery.)

Long Linear Catheter Placed Horizontally

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

The catheter used by surgeons to make the burns on the outside of the heart is unlike a standard point-by-point RF catheter used by Electrophysiologists.

The surgeon uses 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.

Illustration of surgical lesions to outside of heart

The catheter has a notch on the top which can be used to orient the catheter.

Dr. Sherman had ablated the whole of the posterior left atrium including any other areas of the posterior left atrium he could access. Usually 20 to 40 burns are made. The burns can overlap and can be repeated.

“Charring” the “Red Meat”

Dr. Sherman described normal heart tissue as “red meat” which after the ablation looks “charred”. “We just mow the lawn.” Dr. Sherman said his goal was to ablate to the point of complete “electrical silence.”

Ablated heart muscle 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 A-Fib potentials or signal sources are destroyed along with the heart tissue.

Dr. Sherman stated his goal was to eliminate all electrical activity, to basically kill as much heart tissue as he can reach.

Passing the Baton: From Surgeon to Electrophysiologist

In Phase II, Electrophysiologist Dr. Kevin Makati continued Dr. Sherman’s surgical work and eliminated electrical activity in areas of the posterior left atrium wall Dr. Sherman could not reach.

As much as possible, they try to do both the surgery and the catheter ablation on the same day, usually in what he called their Hybrid Lab.

Phase II: Convergent Catheter Ablation

Example of a voltage map during CryoBalloon catheter ablation. Source: K. Makati

Dr. Kevin Makati then described the Convergent catheter ablation (Phase 2).

He used a voltage map to show how, after Surgeon Sherman’s work, there was still electrical activity at the roof of the posterior wall and in the lower wall which he called the “vestibule”.

Using a CryoBalloon catheter, he dragged it to make an ablation line from the Right Superior PV to the Left Superior PV.

“Reducing the critical substrate in the left atrium, you decrease the incidence of fibrillation conduction.” He also ablated in the vestibule to “reduce the substrate available to participate in Atrial Fibrillation.” Basically, he made sure the whole posterior wall was dead and electrically silent.

Thoracoscopic Approach to Close Off the LAA

From the audience, Dr. Mansour asked a question about how the patient seemed to have a “V clip” (AtriClip Pro•V Device from AtriCure) already installed in his Left Atrial Appendage (LAA).

Dr. Sherman explained that the “V Clip” was installed earlier in the week using a thoracoscopic approach (three port holes in the chest rib area).

A thoracoscopic approach works better than a subxiphoid when closing off the LAA, though this does involve two different surgeries for the patient.

Dr. Sherman stated that they do not do a LAA closure if there are clots in the LAA. They first have to use anticoagulants to dissolve these clots before closing off the LAA.

We watched a pre-recorded segment from earlier in the week as Dr. Sherman attached the “V Clip” to the LAA. He had to do a lot of tugging and wrestling with the LAA which is remarkably resilient. He thought he had all the lobes of the LAA included until someone using Transesophageal Echocardiogram (TEE) pointed out that there was one lobe that hadn’t been included. Once this was done, they closed the “V Clip”. There didn’t seem to be any residual LAA stump left over.

Convergent Reported 80% Success Rate

The on-site moderator Dr. Felix Yang from Maimonides Medical Center in Brooklyn, NY stated:

“There have been 10,000 Convergent procedures that have been performed worldwide today. This procedure has undergone an evolution over time…. The LAA closure has become an integral part of this procedure. It’s a good thing to see what happens to this persistent population when you have posterior wall isolation as well as electrical isolation of the appendage.”

To conclude, Dr. Yang stated that the success rate of today’s Convergent Surgery/Ablation is around 80%, and that the complications seen in the first Convergent operations have decreased over the last ten years.

Editor’s Comments:

I’m biased against the Convergent Surgery. I admit it. I consider the Convergent operation barbaric, brutal and excessive. Talk about overkill.

The Surgeon: The surgeon operates on the outside (epicardial) of the heart. Every time I see a live Convergent operation, I get nauseous. I can’t imagine having my posterior left atrium wall destroyed like this. Is it really necessary to completely obliterate (kill) the left atrium wall to make a patient A-Fib free?

I acknowledge that, in some patients, this may indeed be helpful. But is this a case of throwing the baby out with the bathwater?

What’s the point of making all these burns if a patient’s left atrium wall no longer functions?

Do as Much Damage? Or, Do as Little Damage? Surgeons in the Convergent operation try to do as much damage as possible.

EPs do often ablate in the posterior left atrium wall such as by creating a box lesion set. But they try to do as little permanent damage to the heart as possible.

Convergent Surgery Does Lasting Damage to the Heart. In the Convergent surgery, the 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 “charred” scar tissue.

The ability of the left atrium to contract risks being affected (though the posterior wall of the left atrium doesn’t normally contract that much).

Leads to Weakened Hearts: The surgeon does tremendous damage to the posterior left atrium which can never be restored. The heart can’t function normally if the posterior wall doesn’t work anymore.

This may weaken the heart and contribute later to heart problems like congestive heart failure. All too many patients today suffer from weak hearts due to heart muscle damage.

Restore Not Destroy. I admit it. For most patients I’m biased against the Convergent Surgery

Instead of destroying tissue, the goal should be to restore a patient to normal sinus rhythm, to make the heart function normally again. (That’s the goal of catheter ablation.)

If you find any errors on this page, email us. Y Last updated: Saturday, May 2, 2020

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