In a live case from the 2017 AF Symposium, Dr. David Wilber from Loyola University Medical Center showed how he uses the Topera FIRM rotor mapping system to identify rotors in conjunction with a PVI. (‘FIRM’ stands for Focal Impulse and Rotor Modulation.)
Dr. Wilber described how he first does voltage mapping while the patient is in normal sinus rhythm. He started in the right atrium, then moved to the left; he used the FIRM system to map where rotors were coming from. (In patients with persistent A-Fib, he typically finds as many as 4-8 rotors.) He mapped and ablated until there were no more rotors.
Only after using the FIRM system did he do a Pulmonary Vein ablation…Continue reading my report.
Background: FIRM stands for ‘Focal Impulse and Rotor Modulation’; The FIRM mapping and ablation system uses a basket catheter, a panoramic contact-mapping tool by Topera/Abbott Laboratories. Rotors (rotational circuits or focal sources) are underlying drivers that sustain or perpetuate an A-Fib signal after it has been triggered (like an echo).
A three-center 2015 study (Gianni) used FIRM-guided only ablation on 29 patients with persistent or long-standing persistent A-Fib. The centers were:
• The Texas Cardiac Arrhythmia Institute, St. David’s Medical Center, Austin, TX, USA
• The Heart Center Bad Neustadt, Bad Neustadt, Germany
• Baptist Health, Lexington, KY, USA
Undergoing FIRM mapping, 20 patients had persistent A-Fib and 9 patients had long-standing persistent. Doctors found 4 rotors (on average) per patient (with 62% coming from the left atrium) and 1 focal impulse. All these signal sources were successfully ablated.
Follow-up Ablation Results
After a mean of 5.7 months of follow-up, single procedure freedom from A-Fib/Flutter without antiarrhythmic drugs was a low 17%.
Researchers concluded that the FIRM system was not effective in returning patients to normal sinus rhythm (or alternatively moving from the chaotic A-Fib rhythm to a more regular rhythm such as A-Flutter). And only ablating FIRM-identified rotors did not prevent recurrence (i.e., return of A-Fib).
Other Research on the FIRM System
This study confirms the January 2015 AF Symposium presentation, Critical Analysis of the FIRM Mapping System, by Dr. Ravi Mandapati of Loma Linda University,
From a different perspective, Dr. Vivek Reddy offers a real world application of the FIRM system (advantages and problems). See the 2016 AF Symposium presentation: Two Challenging, Difficult Catheter Ablation Cases.
Bottom line for Patients
Even though the FIRM mapping and ablation system seems to currently have built-in limitations, master EPs still use the FIRM basket mapping catheter because it provides a great deal of important information very quickly. It is especially useful in cases of Persistent A-Fib.
Note: The developer of FIRM, Topera/Abbott Laboratories, is working to address shortcomings by developing its own line of mapping basket catheters.
AF Symposium 2016
Two Challenging, Difficult Catheter Ablation Cases with LAA Closure
by Steve S. Ryan, PhD
One of the most interesting and practical sessions was “Challenging Cases in Catheter Ablation and LAA Closure for AF”. Featured were a panel with some of the world’s ‘master’ Electrophysiologists (EPs). Each presented one or two cases of their most challenging and difficult cases from the past year. The panelists were:
• Dr. David Keane, St. Vincent’s University Hospital, Dublin, Ireland (Moderator).
• Dr. Moussa Mansour, Massachusetts General Hospital, Boston, MA.
• Dr. Andrea Natale, Texas Cardiac Arrhythmia Institute, Austin, TX
• Dr. Douglas Packer, Mayo Clinic, Rochester, MN
• Dr. Vivek Reddy, Mount Sinai Hospital, New York, NY
• Dr. Miguel Valderrabano, Houston Methodist Hospital, Houston, TX
• Dr. David Wilber, Loyola University Medical Center, Chicago, IL
Two cases of Persistent A-Fib stood out as significant for readers of A-Fib.com. To learn why, see my ‘Take Away’ comments that follow each case description.
Electrically Dead Left Atrium
Dr. Valderrabano presented the case of a 48-year-old female patient with symptomatic Persistent A-Fib. She had been cardioverted several times and had tried several antiarrhythmic drugs including amiodarone. She had had Pulmonary Vein Isolations (PVI) by other EPs before being referred to Dr. Valderrabano.
Her left atrium was enlarged. Dr. Valderrabano ablated her again but couldn’t isolate her Left Atrial Appendage (LAA) where A-Fib signals were still coming from. He used the Lariat (SentreHeart, Inc.), a noose-like suture delivery device, to close off and electrically remove her LAA.
After these steps, she had a leak from her closed-off LAA which had to be plugged. She was A-Fib free but developed Atrial Flutter which had to be ablated.
After all these ablations, she was finally in sinus rhythm. But at what cost? All the extensive ablations and scarring had made her Left Atrium electrically dead and unable to contract normally (“Stiff Left Atrium”).
The patient knew she might lose contraction of her left atrium, but was most happy to be in sinus rhythm after years of symptomatic A-Fib.
TAKE-AWAYS FOR PATIENTS
Lariat to Prevent A-Fib Signals from the LAA: The Lariat is an occlusion device, and like the Watchman, is normally used for closing off the Left Atrial Appendage (LAA) to prevent A-Fib clots breaking loose and causing a stroke. It’s particularly useful for people who can’t or don’t want to take anticoagulants.
In this case, the LAA was the source of non-Pulmonary Vein (PV) signals (and often is). By removing it, patients can often be restored to sinus rhythm. (Master EPs now consider the LAA the most important source of non-PV triggers. Unfortunately, many EPs are unaware of the LAA’s importance and don’t check it for non-PV triggers during an ablation.)
Stiff Left Atrium: No one wants to lose their Left Atrium’s ability to contract and pump. But in extreme cases, this may happen.
I talked to one of the most experienced EPS in the world who has had to do several ablations which restored a patient to sinus but also rendered their left atrium electrically dead and unable to contract normally. [Note: the Left Ventricle does most of the heavy-duty pumping work.]
His patients, even though they knew the risks, were overjoyed to finally be in normal sinus rhythm. After years of symptomatic A-Fib, they had their life back again.
FIRM Advantages and Problems
Dr. Vivek Reddy presented the case of a 63-year-old male in Persistent A-Fib who had had several ablations before being referred to him. After wearing a Holter monitor for one-week, the data showed an A-Fib burden of 27%, i.e., his A-Fib was very symptomatic and burdensome.
Dr. Reddy did a FIRM-guided ablation, but the patient was still in A-Fib.
Upon closer examination and manual mapping, the ‘renegade’ A-Fib signal source was found and ablated, which restored the patient to sinus rhythm.
Dr. Reddy had discovered the A-Fib signal in the area where the FIRM basket catheter didn’t map. As mentioned in other Symposium presentations, due to design problems, the FIRM basket catheter maps only slightly more than ½ of the left atrium. (New basket catheters to correct this problem are being developed by the manufacturer, Abbott/Topera.)
TAKE-AWAYS FOR PATIENTS
Limited but Extensive Data with Fast Results: Even though the FIRM mapping and ablation system seems to currently have built-in limitations, master EPs still use the FIRM basket mapping catheter because it provides a great deal of important information very quickly. It is especially useful in cases of Persistent A-Fib where it identifies non-PV triggers such as rotors and focal drivers. As Dr. Reddy stated earlier, this is the future of A-Fib ablation.
Choose an EP Who Can Compensate for FIRM Limitations: When choosing an EP to do your ablation, it isn’t enough to select someone who uses the FIRM system. You need an EP who knows the limitations of the FIRM system and how to find and ablate non-PV triggers the FIRM system may miss. The fact that an EP uses the FIRM system is not a guarantee you will have a successful ablation.
The two cases I chose to write about were the most informative for those A-Fib patients seeking to understand the most current treatment options. This Saturday afternoon session was the last of the 2016 AF Symposium.
For more about the Lariat occlusion device, see my brief article: Lariat II Suture Delivery Device.
For more about the FIRM mapping system, see my brief article: FIRM Mapping System—Should Ablation Patients Avoid It?
If you find any errors on this page, email us. Y Last updated: Monday, February 15, 2016
A new video and a new personal A-Fib story. Susan Klein writes that A-Fib runs in her family.
“I come from a long line of people with cardiac rhythm disorders. As I write this, I am 67, female and live in Chicago. At age 42, I realized I hadn’t escaped the family ‘curse’―referred to as “it” or “the mouse running around in my chest.”
Misdiagnosed for Years
Watching my family members suffer with “it”, convinced me that doctors were powerless to stop it. It took me a long time to seek medical advice; and when I first did, I was misdiagnosed.” Continue reading her personal A-Fib story.
A-Fib Patient Story #83
VIDEO: My Family’s A-Fib was Misdiagnosed for Years; FIRM Ablation by Dr. Narayan
By Susan Klein, November 2015
At age 42, I realized I hadn’t escaped the family ‘curse’―referred to as “it” or “the mouse running around in my chest.”
Misdiagnosed for Years
Watching my family members suffer with “it”, convinced me that doctors were powerless to stop it. It took me a long time to seek medical advice; and when I first did, I was misdiagnosed.
Along the way I can’t recall how many times I was told to take the medicine and stop looking for trouble.
Along the way I can’t recall how many times I was told to take the medicine and stop looking for trouble.
Glad I Didn’t Listen to the Naysayers
I’m so glad I didn’t listen, because today I’m A-Fib free and loving it. I owe this to Stanford cardiologist, Dr. Sanjiv Narayan. Please watch the video to learn more about the good doctor’s amazing work.
If you have any questions or want more information, please contact me. Susan Klein, smk.klein(at)yahoo.com
VIDEO: Susan Klein/Breakthrough AFib Care Offered at Stanford Health Care
Description: Susan Klein was like many of the millions who endure the symptoms of atrial fibrillation. Day after day, she could do less and less. After an intense research for definitive treatment, she found Stanford Physician: Sanjiv Narayan, MD, developer of a breakthrough A-Fib mapping technology.
Called ‘Focal Impulse and Rotor Modulation’ (FIRM) Ablation, this technology pinpoints where A-Fib starts in the heart and guides doctors to ablation treatment so definitive that it often becomes a one-time procedure.
Published by Stanford Health Care, Sep 15, 2015. 3:56 min.
We thank Susan for sharing her story of heredity (or genetic) Atrial Fibrillation.
To learn about the FIRM mapping system for catheter ablations, read my article: FIRM (Focal Impulse and Rotor Modulation) for Catheter Ablation of A-Fib by Dr. Narayan of UC San Diego, and my 2014 AF Symposium presentation summary, ECGI vs. FIRM: Direct Comparison, Phase/Waveform Mapping.
For more about hereditary (Familial) A-Fib read answers to these FAQs: “Can I Prevent Familial A-Fib with Diet? Supplements?“, and “Is my Atrial Fibrillation genetic? Will my children get A-Fib too?”
FIRM (Focal Impulse and Rotor Modulation) for Catheter Ablation of A-Fib by Dr. Narayan of UC San Diego
by Steve S. Ryan, PhD
I have received several emails asking why I don’t write about Dr. Sanjiy M. Narayan’s studies. I must admit to not understanding some aspects of FIRM and was hoping further information would make things clearer.
Ablating focal beats and electrical rotors, or as Dr. Narayan describes them, “localized areas of electrical activity” is nothing new. (See 2011 Boston A-Fib Symposium, Using CFAEs in Ablating Persistent A-Fib, and 2009 Boston A-Fib Symposium, CFAEs vs. Dominant Frequency) Dr. Narayan’s FIRM procedure uses the largest 64-pole standard basket catheter to do the mapping and uses “monophasic action potentials” (MAPs) catheter mapping to physiologically identify the A-Fib generating spots in the heart.
Proprietary, Patented Algorithm
What is new is the proprietary, patented algorithm Dr. Narayan uses to display the optical images and movies of the activation. (A description of the signal processing Dr. Narayan uses is found in the article “Computational Mapping Identifies Localized Mechanisms for Ablation of Atrial Fibrillation.”) Topera Medical, which licensed this algorithmic-based mapping system, calls it RhythmView.
This author doesn’t understand how Dr. Narayan’s proprietary system differs from other non-proprietary systems using basket catheters to map focal beats and rotors, with the possible exception that he uses the largest basket catheter with a wide field of view to be able to map almost an entire atria at one time.
Targets Rotors and Focal Beats Before Any Other Ablation Sites
After ablating rotors and focal sources found by his FIRM mapping system, Dr. Narayan also ablates the pulmonary veins utilizing wide area circumferential ablation—similar to what is currently done in most A-Fib centers.
Dr. Narayan targets ablation at rotors and focal beats before any other ablation sites, including the pulmonary veins. “Ablation at only rotors and focal sources revealed by our mapping approach (without pulmonary vein isolation) terminated AF predominantly to sinus rhythm in seconds to minutes.”
According to Dr. Narayan, “patients undergoing this targeted ablation (FIRM) experienced a superior rate of AF elimination in the long-term compared to patients undergoing traditional ablation procedures focusing on trigger mechanisms near the pulmonary veins.” Yet, after ablating rotors and focal sources found by his FIRM mapping system, Dr. Narayan also ablates the pulmonary veins utilizing wide area circumferential ablation—similar to what is currently done in most A-Fib centers.
Others Start By Ablating the PVI First
Dr. Narayan’s approach differs from standard operating procedure in almost all centers which start with ablating or isolating the pulmonary vein openings first before moving to other areas.
To this author, Dr. Narayan’s approach doesn’t make intuitive sense. If the pulmonary veins are still firing when mapping is done of the rest of the atrium, wouldn’t these PV signals interfere with or confuse the mapping? In most paroxysmal A-Fib patients, isolating the pulmonary veins is often all that’s needed to eliminate A-Fib (these patients often don’t have any other sources of A-Fib signals outside of the pulmonary veins).
Dr. Narayan found that patients with persistent A-Fib had more sources than those with paroxysmal A-Fib, though these sources were few in number—only about 2 for both atria. This is in contrast to previous studies which have found a greater number of A-Fib producing spots, especially in persistent A-Fib patients.
Dr. Narayan found that almost one-quarter of A-Fib sources come from the right atrium.
Contrasts with Established Protocols
For persistent A-Fib patients Dr. Narayan makes a left atrial roof line ablation, and for those with typical atrial flutter he makes a cavotricuspid isthmus ablation. No other ablation is performed even for persistent A-Fib. This contrasts with established protocols for ablating persistent A-Fib. (See 2008 Boston A-Fib Symposium, Stepwise Approaches in Ablating Chronic A-Fib.)
PRECISE-PAF trial results of FIRM ablation for atrial fibrillation without pulmonary vein isolation (PVI). This was a multi-center trial performed at nine centers with 33 patients showed a 67% termination of A-Fib, with another 17% showing a greater than 10% slowing in their A-Fib.
This is a relatively few number of patients.
EDITOR’S COMMENTS: Perhaps the most important innovation of FIRM is the ability to map and ablate rotors and focal beats in “seconds to minutes.”
Right now doctors doing ablations on patients with persistent A-Fib spend a great deal of time and effort tracking down and ablating rotors and focal sources of A-Fib. If Dr. Narayan’s FIRM system makes this part of the ablation procedure easier, faster and more accurate, this would be a major medical breakthrough for A-Fib patients and doctors.
(The author admits to not understanding how the FIRM system works compared to other systems using basket mapping catheters.)
But one can question the validity and accuracy of the FIRM system, since it typically finds only about 2 A-Fib sources in each atria.
It’s hard to compare Dr. Narayan’s results or to say his approach is superior to standard Pulmonary Vein Isolation. Most experienced A-Fib centers achieve around a 67% success rate as Dr. Narayan does. Though Dr. Narayan first ablates rotors and focal sources in the left atrium, he does later ablate the Pulmonary Veins like almost all other centers.
(It probably makes more sense to first ablate the PVs, then use the FIRM system to track down any A-Fib
A second important innovation of Dr. Narayan’s FIRM mapping system is the finding that one-quarter of A-Fib signals come from the right atrium. If future trials confirm this finding, doctors might have to change their ablation procedures and direct more attention to the right atrium.
Return to Index of Articles: Research and Innovations
Last updated: Wednesday, September 2, 2015