2018 AF Symposium Live Case: Isolating the Left Atrial Appendage using RF Energy
by Steve S. Ryan, PhD.

Rodney Horton MD
Dr. Rodney Horton from the Texas Cardiac Arrhythmia Institute in Austin, TX, demonstrated in a live case how to isolate the Left Atrial Appendage (LAA) using Radio Frequency (RF) energy.
Side note: If you been in the EP lab before, the first thing you notice when viewing Dr. Horton at work is no one is wearing the lead aprons and protectors required when using fluoroscopy (x-ray). That’s because he uses 3D non-fluoroscopy (no radiation) imaging techniques.
Patient background: An 82-year old male with persistent A-Fib had a previous PVI but still had Flutter. He was also hypertensive. He also had a dual chamber pacemaker. Previously Dr. Horton had isolated the patient’s Coronary Sinus but hadn’t worked on his LAA.
Before the live case, Dr. Horton found that the patient had re-connection in one vein which he isolated before the live case demonstration began.
The Live Case: Mapping and Isolating the LAA


Dr. Horton used a mapping catheter in the Left Atrial Appendage (LAA).
To isolate the LAA, he used 40 watts radio frequency (RF) energy and a contact force sensing catheter with pressure readings above 10 but not higher than 25. The pressure readings indicate how hard the EP is pressing on the RF catheter to make a particular burn.
He discussed that if the LAA wasn’t contracting properly after the ablation, the patient would have to be on anticoagulation for life. (He, of course, discussed this possibility with the patient before the ablation.)
Dr. Horton rarely isolates the LAA during a first ablation unless he is absolutely sure it needs to be done. He stressed that the phrenic nerve often drops over the top of the LAA. For that reason, he doesn’t ablate too deep into the LAA but ablates at the base of the LAA.
Applause, Applause
There was excitement and clapping when he isolated the LAA and the Flutter disappeared as we watched.
Dr. Horton demonstrated for all the attendees that the LAA should also be mapped and isolated. And that isolating the LAA can be very effective in returning a patient to normal sinus rhythm.
Editor’s Comments:



No, no to Fluoroscopy: It’s a type of X-ray and its effect is cumulative. Therefore it should be avoided if possible. (Hence, the need for the staff to wear the lead aprons.)
Instead of fluoroscopy, Dr. Horton uses a non-radiation 3D imaging technique called Intracardiac Echocardiography (ICE), a form of ultrasound.
On a personal note, Dr. Horton has said that not having to wear those heavy lead aprons would probably add 5-10 years to his ablation career.
Importance of the LAA in Isolating A-Fib: More and more EPs are realizing how important the LAA is in mapping and isolating non-PV triggers. Many Master EPs after isolating the PVs, now go right to the LAA as their second isolation target.
What this means for patients: When selecting an EP for your catheter ablation, discuss the Left Atrial Appendage (LAA) as a possible site of non-PV A-Fib triggers. Ask your EP:
“During my ablation, when you’re looking for non-PV triggers, will you also map and isolated the LAA, if necessary?” (You want an affirmative answer to your question.)
If you find any errors on this page, email us. Y Last updated: Sunday, February 25, 2018
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