2020 AF Symposium

Live Case of Difficult A-Fib Ablation of Atypical Flutter

by Steve S. Ryan

Atypical Flutter circuits can be the most difficult to map and ablate. This live case of Atypical Flutter was a very difficult and challenging ablation. It was certainly among the toughest situations electrophysiologists (EPs) will encounter.

This live catheter ablation from Boston was presented via streaming video. We observed Atypical Flutter during this live ablation.

A-Fib Patient History

Dr. Kevin Heist from Massachusetts General Hospital described the patient as a 73-year-old man who had A-Fib and Flutter for 13 years. The antiarrhythmic drugs, dofetilide (Tikosyn) and flecainide, were unsuccessful.

In 2007 he had a successful right atrium Flutter ablation at an outside facility (not Mass. General).

In 2009, while on warfarin, he suffered a spontaneous subdural hemorrhage (bleeding between the brain and the skull) while at work. Fortunately, he lived through it.

In 2013 he had his Left Atrial Appendage closed off by a Lariat device, though they found he still had a small stump of the LAA (which is common after lariat closure).

In 2018 he had a catheter ablation for persistent A-Fib. His Pulmonary Veins (PVs) and his posterior left atrial wall were ablated which terminated his A-Fib, but left him in Mitral Annular Flutter. They ablated extensively particularly in the Coronary Sinus. Finally, they were able to convert him from Flutter to normal sinus rhythm (NSR) by making a Mitral Isthmus ablation line.

2018 Mapping Data was Re-Processed and Updated

Dr. Heist showed the patient’s 2018 mapping. Then he used the new Biosense Webster Carto-3 mapping system with a Smart Touch SF catheter. It can accommodate more points than the traditional system, “it creates a best fit for arrhythmia mechanism.”

He showed the 2018 vectors around the Mitral Annulus which were re-processed through the current Carto mapping system. This electroanatomical system created vectors which showed both directionality and the speed of travel.

Targeted Ablation of Scarring and Reconnection

When Dr. Heist and his team started their initial voltage and activation mapping, they found that a portion of the left vein and the posterior left atrial wall had reconnected, and there was activation of the atypical flutter around the mitral annulus.

In addition, they found passive activation of the left pulmonary vein from that flutter as it traveled across the mitral isthmus line into the left veins posteriorly. They directed their ablation to that point.

With voltage mapping they found quite a bit of scar in the rightward of the posterior wall and quite a bit of scar in the Mitral Isthmus region, but a small channel for activation of the pulmonary vein.

Dr. Heist said: “These advanced mapping systems give you a pretty clear ideas of breakthrough areas. So, we targeted our ablation to isolate the left vein and the posterior wall.” This Flutter seemed to be traveling around the Mitral Annulus and through the Coronary Sinus.

At this point in the procedure, Dr. Heist described his plan to continue to move on to more ablation and if necessary, to Coronary Sinus ablation as was done in 2018 to achieve Mitral Isthmus block.

“We have moved to higher energy and shorter duration lesions and are using 50 Watts for 10-15 seconds commonly to perform typical pulmonary vein isolation. But here we may need deeper lesions than for the rest of the left atrium. We will use 40 Watts with a force of 10 or 15 grams. We’ve been using the lesion index and trying to reach lesion indexes in the range of 500.” (The ablation index is a marker or measure of ablation quality that incorporates power, contact force, and time in a weighted formula.)

Why No Use of Pacing?

Dr. Heist didn’t want to use pacing (entrainment) because he didn’t want to prematurely terminate the Flutter signal. Around this time, they saw some esophageal warming and had to limit their ablations.

Atrial Flutter Termination!

We watched as they actually terminated the Atypical Flutter!

Nonetheless, Dr. Heist said they would continue the ablation in the Coronary Sinus and the Mitral Isthmus line. They might also ablate circumferentially around the Coronary Sinus to make sure there are no potentials present.

As the ablation team continued to ablate in the Coronary Sinus, they answered questions from the Symposium attendees. They then had to end the live case presentation because of time constraints.

Editor’s Comments:

This ablation procedure for Atypical Flutter has got to be one of the most difficult ablation cases I’ve ever seen performed live! Dr. Heist did everything possible to check for hidden or latent arrhythmia signal sources (a characteristic of a “master” EP).

In an email to the me after the AF Symposium, Dr. Heist shared:

• At the end of the procedure, all pulmonary veins and the left atrial posterior wall were isolated.

• The mitral isthmus through which the atypical flutter had passed was completely blocked (and remained blocked when the IV drug adenosine was given).

• No arrhythmia (flutter or fibrillation) could be induced by aggressive rapid pacing. That’s the best possible result for a patient! 

One can’t help but admire Dr. Heist’s and his colleagues’ tenacity in searching for and ablating this patient’s elusive atypical Flutter.

If you find any errors on this page, email us. Y Last updated: Wednesday, August 26, 2020

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