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2020 AF Symposium

Terminate Persistent A-Fib by Ablating Higher Frequency Modulation Areas

by Steve S. Ryan

Background: Previous studies by Dr. Jose Jalife, University of Michigan, Ann Arbor, MI.:
• A-Fib Produces Fibrosis—Experimental and Real-World Data: Dr. Jose Jalife’s ground-breaking research studies with sheep demonstrated conclusively that A-Fib produces fibrosis;
Experiments in Atrial Remodeling in Sheep and the Transition From Paroxysmal to Persistent A-Fib: Dr. Jalife’s later research showed how A-Fib progresses in time from paroxysmal to persistent A-Fib.

Jose Jalife MD

At this year’s AF symposium, Dr. Jalife presented findings by research colleagues showing how leading-driver regions of A-Fib have higher frequency modulation (iFM) areas which, when ablated, usually terminate persistent A-Fib.

His presentation was entitled “Using Instantaneous Amplitude and Frequency Modulation to Detect the Footprint of Stable Driver Regions as Targets for Ablation of Persistent AF.” Dr. Jose Jalife, University of Michigan, Ann Arbor, MI.

Clinical Study

Researchers have used sheep and pigs in previous studies. This time to detect rotors in sheep, researchers developed algorithms based on amplitude modulation (iAM) and frequency modulation (iFM).

They then switched to pigs who underwent high-rate atrial pacing to develop persistent A-Fib.

Frequency modulation (iFM) /instantaneous amplitude modulation (iAM) approach to patients with persistent atrial fibrillation

Using the PentaRay Catheter (Biosense Webster) to produce high-density electroanatomical atrial mapping, they found that regions of higher than surrounding average iFM were considered leading-drivers.

These iFM areas also had the highest dominant frequency. “They are the footprints of rotors.”

Not all rotors are drivers. Only those with the highest frequency and greater stability are A-Fib drivers. “IFM helps identify the regions with the highest frequency drivers.”

Researchers constructed two leading-driver + rotational-footprint maps (rotors) 2.6 hours apart from each other to test for stability and to guide ablation. Leading-driver regions remained in approximately the same spots in each map.

The trial showed high iFM areas are responsible for maintaining persistent A-Fib

Study Results

When these areas were ablated, persistent A-Fib terminated in 12 of the 13 cases (92.3%). Rotational-footprints (rotors) were found at every leading-driver region, but not all rotors had higher iFM. “In pigs, ablation of leading-driver regions usually terminates persistent A-Fib and prevents its sustainability.”

Conclusion

Dr. Jalife concluded that high iFM areas are responsible for maintaining persistent A-Fib. And using iFM results in higher sensitivity and specificity without the need for high resolution and costly panoramic mapping.

Editor’s Comments:

(I had never heard of the term “frequency modulation” (iFM) applied to A-Fib before.)
High Areas of iFM a New Discovery in A-Fib: The researchers have re-defined the field of mapping and catheter ablation.
This research shows that higher regions of iFM help identify the regions with the highest frequency drivers (rotors) and are more easily mapped in persistent A-Fib.

Dr. Jalife and his colleagues have given EPs and researchers a new tool to better ablate persistent A-Fib, the most difficult arrhythmia to fix.

Resource and Footnote
Dr. Jalife added: “The work I described in my presentation was not mine, but the result of a team effort led by a young Spanish physician and scientist named David Filgueiras Rama. David trained with me a few years ago but now has his own independent laboratory at the National Cardiovascular Research Center (CNIC) in Madrid, Spain. The idea of using iFM modulation to localize drivers was an inspiration of Jorge Quintanilla who is the first author in the paper you have cited. Together, Jorge and David generated the hypothesis, designed the experiments and wrote the paper. My roll was primarily advisory, and I helped with the final draft of the manuscript. Thus, I was only acting as a messenger at the AF Symposium.

Quintanilla, JG et al. Instantaneous Amplitude and Frequency Modulations Detect the Footprint of Rotational Activity and Reveal Stable Driver Regions as Targets for Persistent Atrial Fibrillation Ablation.  Circ Res. 2019 August6 30; 125(6):609-627. Epub 2019 Aug 1. https://www.ncbi.nlm.nih.gov/pubmed/31366278  doi: 10.1161/CIRCRESAHA.119.314930.

If you find any errors on this page, email us. Y Last updated: Friday, May 1, 2020

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