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Interview with Michele Straube on Results of Survey of A-Fib Patients and Wearable Devices
by Steve S. Ryan
We are happy share the results of Michele Straube’s survey of A-Fib patients on consumer wearable/portable devices/apps which many of you participated in April 2019. She received a great response―315 replies! You can review the actual survey and tabulated results at: Survey Questions and the Results.
You may want to re-read Michele Straube’s 2010 A-Fib story, Cured after 30 years in A-Fib. She recently had a second catheter ablation June 11, 2020 and is doing fine, “Went for a walk in the mountains yesterday with 500’ elevation gain, and felt good.”
Michele Straube
Interpreting the Survey Data
I asked Ms. Straube to share her insights and conclusions about her survey data and how it might or should affect A-Fib treatment strategies.
“What do you think is important in your survey’s responses?”
It’s important how many people responded, and the fact that these AFib patients are very interested in having data about their condition.
It’s clear that AFib patients are interested in being an active part of the team managing their condition. Doctors should welcome this (but see below).
For device and apps developers: there’s a huge market for wearables with apps that help inform AFib patients and gain peace of mind when making treatment decisions. Current devices don’t necessarily give us all the information we’re seeking.
There should be greater collaboration between the device developers and patients in future research and design.
“What information were you looking for?”
I wanted to know if AFib patients use wearable devices? And if so, why and how they use the data. What device or apps would they like someone to design for them.
“Were you surprised by any of the results?”
I was surprised how many different devices there are that give some kind of relevant data (over 45 different brands), yet virtually none of the A-Fib respondents were 100% satisfied with their device’s capabilities.
About 10% of the respondents said that their doctors were not interested in seeing the data from wearable devices!!!
Many of the respondents wished for device capabilities that already exist; i.e., the devices are not being marketed to the right audience.
“What results do you think should be published?”
I wanted to know how AFib patients currently use the data available and what they wish would be developed.
“How do you think your results should influence A-Fib treatment strategies?”
Educate: AFib patients should be educated about the various types of consumer devices and encouraged to use them to help manage their AFib.
Medical providers: doctors should welcome this independently collected additional data (especially for patients who experience AFib episodes when they’re not in the doctor’s office).
Treatment costs: A patient’s use of wearables and apps can reduce the overall expense of AFib treatment.
Michele shared how she used a wearable device:
Using myself as an example, I take an ECG reading on my device, email it to the doctor’s office, and we discuss what to do about a “bad” reading via email or phone.
The one time my device was not working correctly, I had to go into the office for an official EKG reading, which took up much more of everyone’s time and cost oodles of money … and the end result (modification of my meds) was the exact same had I emailed a reading from my device.
We appreciate Michele’s survey work and sharing the results and her conclusions with A-Fib.com readers.
Review the actual survey and tabulated results at: Survey Questions and the Results.
Michele expressed her gratitude to all who participated in this survey, and to A-Fib.com and other sites that solicited A-Fib patients to take the survey. Michele Straube can be reached at mstraube@mindspring.com
Results of Survey of A-Fib Patients and Wearable Devices
Michele Straube
In the spring of 2019, Michele Straube (who was cured of her A-Fib in 2010), conducted a survey of A-Fib patients about consumer wearable technology and apps designed to collect and share a patient’s cardiac data in real-time. The survey was completed by 315 A-Fib patients.
Read our interview with Michele in August 2020 who shares her insights and conclusions about the survey data.
Results of Survey of A-Fib Patients and Wearable Devices
Q1 The Survey Introduction; completed surveys: 315
Q2: Which type of AFib do you suffer from?
- Paroxysmal (>55% — more than half)
- Persistent (~13%)
- Permanent (~8%)
- No longer in AFib (~15%)
- Other (~7%, variations on the above themes)
Q3: How long have you been diagnosed with AFib?
- Less than 1 year (10%)
- 1-2 years (~22%)
- 3-5 years (~25%)
- More than 5 years (~39%, plus ~4% other)
Q4: Do you regularly use any of these wearable/portable devices/apps to provide you with AFib-related information?
- Handheld (portable) ECG/EKG monitor (~47% — almost half)
- Wristband HR monitor (~32%)
- Wristband ECG/EKG monitor (~15%)
- Lead- and wire-free event monitor (~3%)
- No, don’t use any devices (~13%)
- Other (15%) – BP monitor, implanted loop monitor, pacemaker, etc.
Q5: Brands
- Alivecor/Kardia: 150 (almost half)
- Apple Watch (some version): 62 (20%)
- Fitbit/Garmin (some version) 56 (~19%)
- Ziopatch: 6 (~2%)
- Others: ~40 other separate brands
Q6: What made you decide to regularly use the wearable/portable device/app?
- Prescribed by my doctor (~10%)
- Personal decision (~73%)
- Be informed / peace of mind / decide about meds (101, one-third)
- ID “silent” AF episodes / document AFib to doctor when not in office (60, 20%)
- Reduce ER visits / decide whether to contact doctor (24, ~8%)
- Prevent overdoing it during exercise (18, ~6%)
Q7: If you do use a device/app, which AFib-related information do you find valuable?
- HR – instantaneous reading (~75%)
- Heart rhythm (~71%)
- HR – trends over time (~48%)
- ECG/EKG (~44%)
- HR variability (~35%)
- Sleep data (from CPAP and other device) (~30%)
- BP (20%)
- Oxygen saturation (10%)
Q8: Does having AFib-related information from your device/app change your behavior? How?
- No, does not change behavior (100, almost one-third)
- Yes, does change behavior (a little over two-third)
- Actions to end/prevent AFib (85, ~28%)
- “Emotional comfort blanket” / reduced anxiety (45, ~15%)
- Modify meds (24, ~8%)
- How fast to get to ER, contact doctor (14, ~5%)
- Makes me panic / become obsessed with HR (7, ~2.5%)
Q9: Do you share any of the data with your doctor? How? What does doctor do with it?
- Yes: 177 (more than half)
- No: 87 (~30%)
- What share?
- Rhythm strip (108, one-third)
- HR trends / HR spikes (21 (~7%)
- times / length in AFib (20, ~7%)
- Summaries / trends (14, ~5%)
- Own charts analyzing info (8, ~3%)
- How?
- In person (93, almost one-third)
- Email (61, 20%)
- Automatic access (18, ~6%)
- What does doctor do with it?
- Diagnosed with AFib from device data (5)
- Doctor not interested (30, ~10%)
- Decide what treatment (19, ~7%)
- Pleased for additional info (15, ~5%)
Q10: Think about the AFib-related information you wish you could get from a device/app.
- What would you like someone to design for you?
- Some things asked for already exist—may need to do better education/ marketing
- ID any arrhythmia / name type of arrhythmia (51, ~16%)
- Auto/continuous AF monitoring / 24/7 event recorder (37, ~12%)
- Alert when in AFib (32, ~11%)
- Greater accuracy / fewer “possible”, “unclassified”, “indeterminate” readings (28, ~10%)
- All-in-one watch (ECG/EKG, HR, HRV, BP, oximeter, sleep) (20, ~7%)
- Less bulky, cheaper, easier to read (18, ~6%)
- Greater patient access to device data / automatic interpretation / show trends (18, ~6%)
- How would this feature/information improve your quality of life and/or change your behavior?
- Inform treatment decisions (55, ~18%)
- “Knowledge is power,” peace of mind (35, ~12%)
- Cause and effect / look for triggers, patterns (18, ~6%)
Q11: Is there anything else you’d like to share with the Heart Rhythm 2019 audience?
- Complaints about specific devices
- Have insurance cover cost of devices
- Educate doctors about the existence and value of these devices
- Power to the patient
- “Anyone with arrhythmias should be assigned one of these devices”
- “We need full access to what is happening in our bodies so we can make informed decisions and be partners in our care with doctors”
End of survey and results
Go to our interview with Michele Straube about her survey conclusions.
If you find any errors on this page, email us. Y Last updated: Thursday, August 6, 2020
FDA Approved: CardioInsight (ECGI) Mapping and Ablation System Now Available in U.S.
CardioInsight 3D system vest
Medtronic’s CardioInsight Noninvasive 3D Mapping System (ECGI) has received FDA clearance for use in the U.S. The CardioInsight system is the first non-invasive mapping system in the world.
Dr. Vivek Reddy at Mount Sinai Medical Center in New York City was the first to use the system commercially in the U.S.
CardioInsight Noninvasive 3D Mapping System (ECGI)
The CardioInsight system allows physicians to locate the origin of a patient’s irregular heart rhythms (arrhythmias). Cardiac mapping is traditionally achieved by inserting a catheter into the heart via an artery or vein.
The CardioInsight 3D system instead uses a 252-electrode sensor vest to non-invasively (from outside the heart) map irregular rhythms like A-Fib. The vest is a single-use, disposable multi-electrode vest that gathers cardiac electrophysiological data from the body surface. The 3D mapping system combines these signals with CT scan data to produce and display simultaneous 3-D cardiac maps.
The vest technology contours to the patient’s body and allows for continuous and simultaneous panoramic mapping of both atria or both ventricles, which cannot be achieved with current invasive methods. The 3D cardiac maps can be created by capturing a single heartbeat, and enable rapid mapping of these heart rhythms.
ECGI is a Major Breakthrough in Treating A-Fib
ECGI mapping is certainly one of, or even the most important new development in the treatment of A-Fib.
In 2013, I started reporting about this ECGI system. Prof. Haissaguerre and his colleagues in Bordeaux, France, were very active and instrumental in the use of the CardioInsight system. They are credited with the greatest number of presentations and publications on the system. CardioInsight expanded its rollout to eight different venues in Europe where it tested as well as it did at Bordeaux. It’s now available in the U.S.―great news for patients.
Back then, I predicted that “the ECGI system, barring unforeseen circumstances, would rapidly supersede all other mapping systems and will become the standard of care in the treatment of A-Fib patients.”
David Neth wearing ECGI vest before ablation by the Bordeaux Group
Not only does the CardioInsight (ECGI) system produce a complete, precise, 3D, color video of each spot in a patient’s heart producing A-Fib signals, but also the video can be done by a technician before the procedure right at the patient’s bedside rather than by the electrophysiologist (EP) during an ablation. It also can be used during the procedure, for example to re-map an ablated area.
Dr Vivek Reddy stated: “This system shifts mapping away from the EP lab, potentially saving time and enhancing the patient experience.”
The CardioInsight map is a better, more accurate, more complete map than an EP can produce by using a conventional mapping catheter inside the heart.
Should You Wait on Your Ablation for ECGI Mapping?
From a patient’s perspective, CardioInsight (ECGI) reduces both the time it takes to do an ablation and the number of burns a patient receives.
The question for patients is, should you wait on having an ablation till a CardioInsight mapping system is available at your center?
The CardioInsight mapping system is most effective in cases of persistent or long-standing persistent A-Fib where non-PV triggers have developed. Most cases of short-duration, paroxysmal A-Fib haven’t usually developed a lot of non-PV triggers.
Hence, if you’ve only been in A-Fib for a relatively short time and are still paroxysmal, it’s probably not worth the wait.
Medtronic Rollout of CardioInsight System
Medtronic will employ a strategic rollout of the technology in the geographies where it is cleared. I will try to report when an A-Fib center in the U.S. receives a CardioInsight system..
To read more about the CardioInsight (ECGI) system, see my article, How ECGI (Non-Invasive Electrocardiographic Imaging) Works.
Disclosure: Dr Vivek Reddy consults for and receives research funding from Medtronic.
AliveCor Kardia May be Big Winner in Britain’s NHS Plan
AliveCor, maker of the Kardia ECG smartphone attachment to detect Atrial Fibrillation, may be a big winner in a plan by the British National Health Service (NHS).
AliveCor Kardia attached to a smartphone
Dr. David Albert, AliveCor founder, said the British plan opens the door to the NHS buying AliveCor devices for all 2 million atrial fibrillation patients in England.
The NHS has announced plans to give millions of patients free health apps & connected health devices in a bid to promote self-management of chronic diseases.
The plan is expected to “save money and lives by preventing strokes.” About 20 percent of British A-Fib patients have strokes. The program will start in April 2017.
The AliveCor Kardia, cleared for use in the US by the FDA, attaches to Android and Apple Devices and by pressing the sensors with your fingers (or thumbs), capture single-lead, medical-grade EKGs in just 30-seconds. Instantly you know if your heart rhythm is normal or if atrial fibrillation (A-Fib) is detected in your EKG. Data can be captured and sent to your doctor.
Request to Our Readers
Is anyone using the latest AliveCor® version, ‘Kardia™ Mobile’? (Model 1141, out since Feb. 2016) I want to update our Feb. 2015 review.
How do you typically use it? Are you satisfied with the performance? Do you transfer the data to your doctor?
Will you share your product experiences with me? Just shoot me an Email with your impressions.
Wearables in Healthcare: You can Help Develop A-Fib App
It’s early days for wearables in healthcare, but there’s a lot of potential.
In the near future, an Apple Watch or Android Wear could detect if the wearer is experiencing Atrial Fibrillation. A preliminary algorithm (app) to detect A-Fib has been developed by researchers at UCSF and engineers at Cardiogram, Inc.
Sample of A-Fib app on Smart Watch
The mRhythm Study: You Can Help Develop the Smart Watch App
The researchers need your help now. If you have an Apple Watch or Android Wear—regardless of whether you have A-Fib—you can contribute your data to help make the algorithm more accurate.
The mRhythm Study is being run with the UCSF Health eHeart Study, using Cardiogram to train a deep learning algorithm to detect atrial fibrillation.
To Participate in the Study: Visit the mRhythm Study website and scroll down the page and look for ‘We Need Your Help.’ At the bottom of the page, you can then read answers to ‘Frequently Asked Questions’.
See How the System Works: To see the graphic displays of how the system works, go to Cardiogram, Inc. or see the Apple Watch graphics in particular.
What atrial fibrillation and normal heart rhythm look like when measured on a watch.
What This Means for Patients
Each year, more than 100,000 strokes are caused by A-Fib. But all too often, their A-Fib is “silent” with no obvious or noticeable symptoms. In these cases, their A-Fib is undiagnosed until they have a stroke. Only then do they find out they have A-Fib (…if they survive). About 50% will have a disabling stroke.
If the Smart Watch algorithm app works as intended, anyone with an Apple Watch or Android Wear will be alerted if they are experiencing Atrial Fibrillation.
For the undiagnosed, their A-Fib will be ‘visible’ and no longer be “silent.” They will know if they are at risk of an A-Fib stroke and can get the proper preventive treatment.
Today patients rely on an ECG in a doctor’s office or the use of a Holter monitor to detect A-Fib. Instead, a Smart Watch with the A-Fib app can extend a patient’s monitoring period to a year (between doctor’s visits) or on an on-going basis.
Amazing! Think of all the lives saved and debilitating strokes avoided! The A-Fib Smart Watch app has the potential to revolutionize the field of A-Fib monitoring.
My 2015 Top Five List: Advancements in the Treatment of A-Fib
Looking back over 2015, I found five significant developments for those ‘living’ with A-Fib and those seeking their ‘cure’. My ‘Top Five List’ focuses on the Watchman device, a Pradaxa antidote and research findings about lifestyle choices, and reducing fibrosis.
1. FDA Approves the Watchman Device
The Watchman is positioned via catheter
Anticoagulant Alternative: Because A-Fib patients are at high risk of stroke and clots, a blood thinner (anticoagulant) like warfarin is often prescribed. If you can’t or don’t want to be on blood thinners, you had few options.
That was until March 2015 when the US Food and Drug Administration (FDA) approved the Watchman device. There’s now an option to blood thinners! The Watchman device (Boston Scientific) is inserted to close off the Left Atrial Appendage (LAA), the origin of 90%-95% of A-Fib clots.
To read my complete Top Five List…go to My 2015 Top Five List: A Review of Advancements in the Treatment of A-Fib->.
My 2015 Top Five List: A Review of Advancements in the Treatment of A-Fib
With the beginning of a new year, we often look back and measure how far we’ve come. In 2015, I found five significant advancements in the treatment of Atrial Fibrillation.
1. FDA Approves the Watchman Device
The Watchman is positioned via catheter
Anticoagulant Alternative: Because A-Fib patients are at high risk of stroke and clots, a blood thinner (anticoagulant) like warfarin is often prescribed. If you can’t or don’t want to be on blood thinners, you had few options.
That was until March 2015 when the US Food and Drug Administration (FDA) approved the Watchman device. There’s now an option to blood thinners! The Watchman device (Boston Scientific) is inserted to close off the Left Atrial Appendage (LAA), the origin of 90%-95% of A-Fib clots.
It’s not an absolute guarantee you will never have a stroke―but neither is taking warfarin or the newer anticoagulants. For more, see Watchman Device: An Alternative to Blood Thinners.
2. Research: Watchman Better Than a Lifetime on Warfarin
Warfarin (Coumadin)
The Watchman device isn’t simply an alternative to taking warfarin, clinical trials show it’s actually better. Patients with the Watchman had fewer hemorrhagic strokes and less bleeding compared to patients on warfarin. (Warfarin and other anticoagulants work by causing bleeding and are inherently dangerous.)
It’s too early to say the same about the newer anticoagulants like Pradaxa, Xarelto, Eliquis and Savaysa/Lixiana with their short history but one would expect the same general principles to apply. For more, see Watchman Better Than Warfarin.
3. Antidote for Pradaxa
Praxbind: Pradaxa antidote
Up to now, patients on Pradaxa have been bleeding to death in the emergency room while doctors were powerless to stop their bleeding and could only stand by and watch them die. See Stop Prescribing or Taking Pradaxa.
In October 2015, the FDA granted “accelerated approval” to Praxbind, the reversal agent (antidote) to Pradaxa (Boehringer Ingelheim). Praxbind (idarucizumab) is given intravenously to patients and reverses the anticoagulant effect of Pradaxa within minutes.
Note: The reversal agent, Andexanet Alfa, is on FDA fast track and is expected to be approved by mid-2016 as an antidote for Xarelto and Eliquis (Factor Xa inhibitors).
4. Life Style Changes Can Make Some People A-Fib Free
Weightloss
Weight Loss: A weight loss program and counseling in Australia has worked so well that some patients have become A-Fib free.
In his Adelaide clinic, Dr. Prashanthan Sanders convinces his overweight A-Fib patients to buy into the program, lose weight, and keep it off. This holistic approach to health has also been successfully applied to other A-Fib contributing factors such as diabetes, sleep apnea, hypertension, binge drinking and smoking. See Weight Loss Key to Reverse Atrial Fibrillation, Improve Ablation Success.
Exercise
Exercise: But not everyone can lose weight and keep it off. And other risk factors like hypertension and diabetes are more difficult to permanently change.
The same Australian researchers found that exercise improves A-Fib (even obese A-Fib patients benefit from exercise). Supervised aerobic and strength exercises reduced A-Fib by 84%.
Combine for Best Results: Exercise and weight loss together produced the best results. An astounding 94% of obese patients who both lost weight and exercised regularly were A-Fib free after rhythm control therapy (i.e. antiarrhythmic drugs and/or catheter ablation).
Couch Potato Warning: If you don’t exercise regularly, you’re almost guaranteed to stay in A-Fib. Even with rhythm control (antiarrhythmic drugs and/or ablation), 83% of the low-fitness obese patients had A-Fib.
5. Research Studies: Preventing Fibrosis
Fibrotic cells
A-Fib produces fibrosis, and up to now, was considered permanent and irreversible. Fibrosis is fiber-like scar tissue that stiffens and weakens the heart muscle which reduces pumping efficiency and leads to other heart problems. (See Fibrosis and A-Fib).
Dr. Jose Jalife’s experimental studies with sheep found that a Gal-3 inhibitor (GM-CT-01) actually reduced or prevented fibrosis. Better yet, instead of having to wait years for possible FDA approval, a natural supplement, Pecta-Sol C (Modified Citrus Pectin) works like a Galectin-3 inhibitor.
For A-Fib patients, this may provide the means to avoid fibrosis or repair fibrotic heart tissue. (See Galectin-3 Inhibitor Prevents A-Fib).
A Personal Prediction
WATCHMAN device
On a personal note, I’m excited about the great potential of the Watchman device to significantly reduce or eliminate the threat of strokes—especially in the elderly―even if they don’t have A-Fib.
Imagine a world where stroke risk could be eliminated by a simple 20-30 minute procedure. The Watchman device (and other occlusion devices) may change the way elderly medicine is practiced.
If you find any errors on this page, email us. Y Last updated: Saturday, February 16, 2019
Should the Left Atrial Appendage (LAA) be Removed in Patients With A-Fib?
Dr. Dhanunjaya Lakkireddy
AF Symposium 2015
Should the Left Atrial Appendage (LAA) be Removed in Patients With A-Fib?
by Steve S. Ryan, PhD
Leading doctors and researchers have pointed out the importance of the Left Atrial Appendage (LAA) particularly when ablating persistent A-Fib. In the Bordeaux group’s Five-Step Ablation Protocol for Chronic A-Fib, after isolating the Pulmonary Veins (PVs), their next step is to look for A-Fib signals coming from the LAA. In 2010, Dr. Andrea Natale and his colleagues showed that in 30% of A-Fib patients, the LAA was the only structure that had A-Fib signals. (Circulation 2010.)
In his presentation, Dr. Dhanunjaya Lakkireddy from the Un. of Kansas Hospital in Kansas City, MO, confirmed these findings. After the PVs, “the LAA is the most common source of (A-Fib) focus triggers and other A-Fib signals.”
In Older Patients the PVs Have No A-Fib Signals
He further stated that in patients over 70 years old, especially women, the LAA plays a more important role so much so that the PVs are often silent.
How Removing the LAA Affects Left Atrium Pumping Volume
Removing or closing off the LAA reduces the pumping volume of the left atrium by 15% to 30%. But after the LAA is removed, the overall left atrium volume improves.
Removing The LAA Reduces Natriuretic Peptides―But The Heart Compensates Over Time
The LAA is responsible for neuroharmonal changes such as natriuretic peptide levels (i.e., regulates the amount of sodium in the urine) which are important for bodily functions such as thirst. When the LAA is removed, natriuretic peptide levels go down. But Dr. Lakkireddy’s research shows that over time these levels normalize. Other heart areas such as the right atrium compensate and produce more natriuretic peptides to make up for what the LAA used to produce.
Removing the LAA Lowers Blood Pressure
Removing or closing off the LAA often improves blood pressure by dropping epinephrine (adrenaline) levels and lowering (“down-regulating”) the
renin-angiotensin system (hormone system that regulates blood pressure and fluid balance).
Removing the LAA Improves Recurrence Rates
Dr. Lakkireddy found that removing or closing off the LAA at the same time as a catheter ablation for A-Fib reduces recurrence rates by 29%.
Editor’s Comments:
Why LAA A-Fib Signal Sources in Older People—Why Do PVs Go Silent?
One of the most important findings of Dr. Lakkireddy’s research is that in older people the LAA is the most important source of A-Fib signals, so much so that the PVs are often silent. This is counter-intuitive and hard to understand. If, as we know from years of previous research, A-Fib usually starts and is most often found in the PVs, why do the PVs go silent and A-Fib activity mostly move to the LAA in older people? What is the physical or chemical mechanism that causes this major change?
Sea-Change in Ablation Strategy
Dr. Lakkireddy’s presentation was the most important and ground-breaking for older A-Fib patients. It should change the way ablations are performed on older people. If you are over 70 years old, in persistent A-Fib and aren’t very active, you must seek out EPs and centers who understand and ablate the LAA. Most EPs don’t even look at the LAA as possible A-Fib signal sources. Don’t rely on your local EP to learn about this research and adopt any requisite new ablation strategies.
In Older A-Fib Patients the LAA Should be Removed
It certainly looks like, in the case of older people with A-Fib, the LAA should be removed by an occlusion device (either the Lariat or by surgery [AtriClip]). In addition to the known benefit of reducing A-Fib stroke risk (90%-95% of A-Fib clots come from thee LAA), the LAA is a major and often the only source of A-Fib signals in older people.
Little Downside to Removing the LAA
And according to Dr. Lakkireddy, there is very little downside to removing the LAA.
Blood pressure goes down, over time natriuretic peptide levels return to their pre-LAA levels as the heart compensates, the lost LA pumping volume does improve, and recurrence rates are reduced when the LAA is removed.
Older people who are less active may not even notice the loss of LAA pumping volume or the reservoir or surge effect of the LAA. (On the other hand, an active athletic senior may be affected by the loss of pumping volume if the LAA is removed.)
LAA Can Be Removed Before or After an Ablation
In the case of a catheter ablation for A-Fib, it may not be necessary to remove the LAA at the time of the ablation. Since it is a safer procedure than even an A-Fib ablation, the LAA could be removed three months before or after a catheter ablation.
Return to: AF Symposium: Steve’s In-Depth Reports Written for Patients
Last updated: Friday, March 6, 2015
Obesity Produces Fibrosis, But Getting Lean Reverses Fibrosis (in Sheep)
AF Symposium 2015
Dr. Prashanthan Sanders
Obesity Produces Fibrosis, But Getting Lean Reverses Fibrosis (in Sheep)
by Steve S. Ryan, PhD
In a fascinating experimental study with sheep, Dr. Prashanthan Sanders from Royal Adelaide Hospital in Australia, overfed sheep so that they developed sustained obesity for 72 weeks. Their fibrosis increased. Their atria were damaged by fibrotic tissue replacing normal atria muscle. As the sheep moved from being overweight to obese, it was progressively easier to induce A-Fib.
Then Dr. Sanders made the sheep lose weight. With a 30% weight reduction, the fibrosis was no longer present! The sheep were similar to the lean sheep controls.
Dr. Sanders used activation mapping to show that in the obese sheep there was an increased delay in activation suggesting delayed conduction. It took a longer time to activate the atria. But when the obese sheep lost weight, conduction became normal. Also there were improvements in left atrial pressure, inflammatory cell counts and fibrosis, atrial TGf beta 1 and reversal of connexin-43 and ETR-beta (which contribute to fibrosis).
Hypertension and A-Fib in Sheep
Dr. Sanders also stimulated sheep into progressive hypertension for 15 weeks. As with the obese sheep above, these hypertensive sheep developed fibrosis. And activation mapping again showed delayed and abnormal conduction.
Sleep Apnea and A-Fib in Animals
Citing other research, including from Dr. Andrea Natale’s group, repetitively blocking off breathing as in sleep apnea developed increased fibrosis as well as slowed atrial conduction, increased atrial size, and induced more atrial fibrillation.
More Risk Factors Lead to Persistent A-Fib
Dr. Sanders pointed out that A-Fib patients with cardiovascular risk factors like obesity, hypertension, and sleep apnea are more likely to progress to persistent A-Fib than individuals with few or no risk factors.
Fibrosis Produces More Fibrosis
Fibrosis (interstitial fibrosis) is the main factor in changing the atrial substrate. Voltage maps of fibrotic atria show large areas of low voltage, increased areas of scarring, and a more complex electrogram resulting in abnormal conduction. According to Dr. Sanders, fibrosis produces more fibrosis. “There is clear evidence that A-Fib feeds back on itself to remodel this process, and there is even a suggestion that it may induce further atrial fibrosis.”
Editor’s Comments:
(Readers of this report may also want to read Dr. Jose Jalife’s similar experimental sheep studies where, among other findings, he proved that pacing sheep into A-Fib produces fibrosis. See Experiments in Atrial Remodeling in Sheep and the Transition From Paroxysmal to Persistent A-Fib.)
In a previous report Dr. Sanders described the great results he is achieving by having his overweight A-Fib patients lose weight, buy into the program and keep the weight off. Sometimes this life style change alone makes them A-Fib free. But not everyone can lose weight and keep it off. Other risk factors like hypertension and diabetes are more difficult to permanently change. And once A-Fib is well established, life style changes aren’t as effective. Though life style changes certainly do improve overall health and heart health.
Fibrosis is Usually Permanent and Irreversible
Unlike some of Dr. Sanders results with sheep, fibrosis in general is considered permanent and irreversible.
Life Style Changes Usually Not Effective in Lone A-Fib
Approximately half of people with A-Fib have no risk factors or co-morbidities (which used to be called “Lone A-Fib.”) I, for example, developed A-Fib at age 54 when I was in perfect health, running track and 5ks, lifting weights, etc. Life style changes aren’t always effective in cases of Lone A-Fib.
Risk Factors lead to persistent A-Fib
Why do some people with A-Fib stay Paroxysmal for years while others progress rapidly to Persistent A-Fib? Perhaps Dr. Sanders has discovered the reason. Risk factors or co-morbidities like obesity, sleep apnea, hypertension, diabetes, etc. make people more likely to transition from paroxysmal to persistent A-Fib. Patients with A-Fib risk factors should be warned of this danger.
Fibrosis Produces More Fibrosis
Here’s yet another scary thought for anyone with A-Fib. According to Dr. Sanders, fibrosis may feed upon itself producing yet more fibrosis.
Though this isn’t normally done today, anyone diagnosed with A-Fib ought to have a heart MRI to measure exactly how much fibrosis has developed in their heart and how much and how fast it is progressing.
This danger of fibrosis progression is yet another incentive to consider a catheter ablation in order to be A-Fib free with no further progression of fibrosis.
Return to: AF Symposium: Steve’s In-Depth Reports Written for Patients
Last updated: Friday, March 6, 2015
The Virtual Heart Computerized Simulation – Dr. Natalia Trayanova
AF Symposium 2015
Dr. Natalia Trayanova
The Virtual Heart Computerized Simulation
by Steve S. Ryan, PhD
The most hopeful, promising research of the 2015 AF Symposium was presented by Dr. Natalia Trayanova of Johns Hopkins Un., Baltimore, MD. She described the “virtual heart”—a computerized model to simulate an individual patient’s heart.
A Computerized Model
The idea is to build computerized models that can be used to guide an individual patient’s therapy. She previously simulated a heart attack in a specific region of an individual heart and how it affected the dynamics of that specific heart.
Using the virtual heart computerized simulation, she can, for example, program in not only how much fibrosis an individual heart has but its structure. (Is the fibrosis circularly-distributed? Does it have a complex shape or is it patchy?)
The Bordeaux Group Patient Data
Dr. Trayanova is rapidly developing more atria data and experience. The Bordeaux group is providing her patient data from their ECGI body surface potential mapping system (CardioInsight). She has done approximately a dozen retrospective studies using the virtual heart technology (as of January 2015).
The Virtual Heart Simulation images
How it Works
Dr. Trayanova and her team start by doing an MRI scan. Then they hyper-enhance segments which correspond to areas of fibrotic remodeling.
The next step is to develop a computational mesh that incorporates representations of ion channels, calcium cycling and other electrophysical aspects of an individual’s atria. All this is incorporated into patient-specific geometry of the model.
What the Model Can Reveal
Then they let the model run and see what the arrhythmia looks like. Does the fibrotic substrate anchor rotors in particular locations? What are the spatial characteristics of the regions where they are located? Can these spatial metrics guide where the proper ablation should be?
Dr. Trayanova’s team merges these virtual atria with a CARTO map to predict where the catheter should ablate.
Editor’s Comments:
The potential of Dr. Trayanova’s research for A-Fib patients is incredible! Imagine getting an MRI and knowing where your A-Fib is coming from, how your A-Fib affects and works in your heart both now and in the predictive future, how various A-Fib drugs can be expected and predicted to affect your heart, how much and what kind of fibrosis you have, how you can expect your fibrosis to progress and affect you over time, what therapies should be done in your particular case, if you need a catheter ablation, where exactly in your heart the EP needs to ablate, and to be able to accurately predict whether or not or how fast you will progress from paroxysmal to persistent A-Fib based on computer models that mirror your own heart.
Dr. Trayanova’s research has the potential to radically change the way A-Fib is treated. Almost all the uncertainties EPs and A-Fib patients now have to deal with can potentially be eliminated with the virtual computer reconstruction of individual A-Fib hearts.
Return to 2015 AF Symposium: News and Views
Return to 2015 AF Symposiums: Indepth Reports for Written for Patients
Last updated: Sunday, April 19, 2020
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