For some time I have questioned whether my HR during exercise is somehow being suppressed by taking Flecainide as when I compare my HR recorded on my Garmin during exercise (mainly running) with that posted by my colleagues, my HR is significantly lower than all others. I know that when I was taking Bisoprolol (Beta Blocker) it made a big impact on my HR and my ability to exercise and in consultation with my EP, we took me off it.
I have come across the below research paper that established in their sample, that the max HR achieved during exercise for those on Flecainide was 12% of theoretical Max HR lower than those not on Flecainide. Looks like my suspicions have been confirmed.
On 200mgs Flecainide (& no other drugs) I felt my heart rate was down from 60 ish to 55 ish. I also feel moderate exercise rather than 'pushing yourself' is best to stop AF breaking through on this drug. I am 70 this year and have been monitoring my AF/health carefully for 9 years.
Does it matter though? Since you have AF surely what matters is that the Flecainide allows you to exercise more as you'd wish and still be in NSR? The exercise will still be beneficial.
I posted as an observation and info for others as I like to understand consequences and implications and so hopefully be able to make informed decisions.
Finding this info has helped me understand why my HR is lower than expected and as you say, allowed me to exercise more as I desire and keep my heart otherwise healthy.
To some extend, it helps and is a comfort in that it implies my suspected lower HR is not due to some otherwise unidentified issue (result of Ablation / Covid / vaccination etc) that I might otherwise be concerned about.
It's really Integrating how different people respond differently to Flecainide too. When I was on Bisoprolol- which I hated because I was cold all the time and my.legs ached walking uphill or upstairs- my HR was low most of the time. As soon as I'd got used to the Flecainide I started to feel better - higher body temperature, no more tingling and enough energy to clean hills and jog for 30 seconds during interval training. My resting HR went up and I felt better for it. The dose I was on didn't stop episodes altogether but I definitely felt better between them. Titrating right now 10 months post ablation. Things seem to be on track.
For me, Flecainide doesn't appear to affect my resting HR (55) but has lowered my exercise HR whilst at the same time improving my exercise tolerance.
Where once a HIIT session on an exercise bike would have my max HR reaching over 180, when the Flecainide is working it stays below 150 for the same output (watts / kg) and I feel much better during and after a session.
However the effect has diminished of late and sometimes Flecainide does not work either at rest in reducing afib or during exercise to keep HR down or both.
I'm now on Verapamil which appears to be keeping afib at bay (only a week in so early days). This drug seems to have also dropped my resting HR down a couple of notches without any noticeable adverse effects
My exercise HR is down but not to the same extent as Flecainide, which I find surprising.
The report also identified that in the sample, resting HR was not effected by Flecainide, only HR during exercise.
Interesting that you have identified that on flecainide you can produce the same output at a lower HR. That would suggest an improvement somewhere in your oxygen use efficiency?
Recently, my AF has been exclusively triggered by exercise and so I am now closely monitoring HR during exercise and keeping below a self imposed max resulting in my easing off on effort for hills (both cycling and running). No HIIT sessions for me as the objective is to avoid any episodes as I wish to avoid any long term impact and concerned the more episodes I have, the more entrenched it becomes and increased intervention will be required.
For this reason, I’m reluctant to go back to weight training and will tentatively return to swimming as I do not have a HR monitor for swimming and so it’s hard to manage.
Speed. I'm slowly accepting the same issue with exercise and afib. Excercise does appear to be a major trigger for me and swimming especially, which is a bugger having had knee replacement surgery meaning it has been my go too excercise.
Steady state cycling also appears to trigger it sometimes, even if I keep my HR around 120.
The approach from my cardiac doctors appears to be very much hit and miss and / or suck it and see.
I'm experimenting myself with Flecainide and Verapamil. I was on Bisoperol but that was a killer in terms of exercise ability, brain fog and gut rot.
Talking of killers, are you on an anticoagulant? I wasn't as the docs thought my relatively low HR would protect me from a stroke, then I had a mini stroke which scared the beejeezus out of me. My Edoxaban is the one drug I religiously take.
My self imposed max HR is 130 so generally aim to be at 125 during exercise, both running and cycling. Once I pop, it can take 10-15 hours before NSR after PIP. (FYI I’m on 50mg twice daily but always time a dose for 2 hrs prior to exercise, sometimes doubling up - this all in consultation with my EP).
Bisoprolol just destroyed any attempt at exercise as heavily capped my max HR.
I’m on Epixaban as anti-coagulant 5 mg 2 x daily- likewise, wouldn’t miss it ever. Had TIA after run 5 years ago. Very minor and almost unnoticed / diagnosed. The biggest risk to me enjoying exercise would surely be a stroke.
Does your Af come on during the exercise or after when your are resting? If I exert my upper body, i.e lifting or straining pulling, it usually brings on an attack later that day or when I am dropping of to sleep
I previously suffered from A Flutter where my episodes would occur the following day / morning but there were 2 triggers, exercise or excess alcohol. The common for the 2 is dehydration and that may well have been the true trigger, the others just creating this situation. I would never be symptomatic during either event, always the morning after.
For comparatives, when my AF pops during a run (almost exclusively whilst running currently) my HR generally hits about 215 (steady exercising), would hate to think what it would reach during HIIT session. Will drop to 120 / 130 on slowing to easy and then 110/115 walking. On resting can switch between 80/85 and 105/110.
My HIIT sessions are on a Wattbike and when my heart decides to go on one it generally never goes above 180 and quickly drops back to 100 within 5 mins of taking it off the gas. Often puts me in afib though. When things are good at max exertion it tops out at about 150 and I don't go into afib.Running, on the other hand, I can often go upto 180 just jogging and upto 220 if I push it, something I regularly did - and the cardiologist said, only a couple of years ago, that I was just unfit!
I try to stick to steady jogging/walking to keep me at around 130 but sometimes my ticker isn't having any of it and goes straight to 170ish as soon as I start the jogging phase.
They’ve got Wattbikes at my gym - they are excellent but suspect I will never get to use them properly as it will put me into AFib.
Can you tell during exercise if you are in AFib? Even when I pop on a run, I will only identify it from my Garmin HR monitor as I will be checking it every few minutes. Without the HR monitor I would not be aware though I suspect after 5-10 minutes, my performance would start to drop. In the past, before I started watching my HR during a run, I have only realised I’ve been in AFib when I’ve downloaded and looked at my Garmin charts, though sometimes I’ve felt the run was slower / harder than it should have been.
I do know that if my HR goes over 150, then I’m in AFib.
Once in AFib, I don’t drop out again even if I slow up. I used to think I did as it would drop down from 215 to say 120 but it was actually just AFib under low stress.
I use an app called Fibricheck on my mobile to confirm that I'm in Afib at the gym.
I can be in afib at 50 bpm so HR is not a reliable marker for my afib.
I can generally keep my HR down on the bike and the rower and stay in NSR, it's almost any amount of running that sets me off. Once in afib it takes a takes maybe 12 hours or longer to get back to NSR
I was on it for years and never noticed any difference. However, I don't do really high intensity stuff, more like jogging (though I like to call it running) so maybe it didn't notice.
Unfortunately I didn’t wear a HR monitor prior to being symptomatic and so I don’t have any recorded direct comparisons.
It became apparent though that my actual max HR achieved while exercising hard was well short of my theoretical max HR (220 less age) and much lower than my colleagues. I therefore think that now my pace is also restricted compared to what it would be flecainide free, but that’s the price of managing my AF. No more chasing PBs!
That’s right. It is prescribed in order to manage the arrhythmia. However, it has been demonstrated that there is also an unintended impact on HR under exercise, my focus here being on strenuous exercise (80-90% theoretical Max HR). The research shows that there is no impact on resting HR, only under exercise. Presumably the impact rises from zero at rest as HR increases. This is different to Beta Blockers that I understand suppress the HR across the board.
What I’m trying to inform here is that Flecainide users who also exercise and monitor their performance should be aware of the impact of Flecainide on their HR under moderate / strenuous exercise. This may help explain some vatriances / changes they have experienced.
I believe the impact of Beta Blockers is widely understood but not that of Flecainide.
Not quite: For me I would expect during exercise whilst in NSR, that the Flecainide would limit my HR so that for a given “perceived effort”, (that’s how much effort I felt I was putting in, say 80% or 90%), both my HR AND output (pace / speed etc.) would be lower. So by having my HR limited by flecainide, it means I can’t perform so well.
Having said that, unless I’m reading it wrong, MisterMagoo suggests that although his HR is lower, his performance is not decreased (hence my comment that it suggests an improvement in oxygen use efficiency).
Regarding not pushing the envelope- exactly. For my longer term health and QOL, I’ve accepted that it’s best to find a compromise of continuing to exercise but managing the intensity to a level that doesn’t trigger AFib. At the moment, it looks like the sole trigger for AFib for me is exercise intensity (expressed by HR) which if consistent, provides the parameters for me to effectively manage / avoid it. Nothing else appears to trigger it. However, I do need to be careful that there may be things (caffeine / alcohol / stress etc.) that may effect my sensitivity to exercise (if that makes sense - I.e the HR trigger level may change depending on exposure to these others)
Got it. As a matter of interest have you tried nasal breathing whilst exercising? I am a lightweight compared with what you do but find a noticeable difference in tolerance and stamina as a result. Just been reading James Nestor's book Breath. Very interesting.
I’ve not and I am aware that I seem to breath through my mouth all the time and more than most. I’ve always found it unnatural but maybe I should consciously work on changing it and see what impact it has. Thank you for the reference.
A recent visit to my Cardiologist here in Germany, resulted in a suggestion that I reduce my dose of Flecainide by 50mg. She said that my Heart Rate was too low, and said she thought that was due to the Flecainide. I have not yet done it, as I am afraid to. While still in the USA several years ago, I was having breakout Afib, a few times a month. My Doctor there, doubled my dose from 50mg twice daily, to 100mg daily. I was also taking Metoprolol at the time, also prescribed by him. I then moved to another State, and my Doctor there, said he thought my afib was actually being caused by the Metoprolol, and took me off it. That was a real roller coaster ride. I had almost constant Tachycardia, and thought I would die. Eventually though it stopped. I have not had a single episode of afib since. That was four years ago. Now I am told to reduce my Flec as well. This time however I am scared. Especially since she only wants me to reduce it by 50mg. I am afraid to take a half dose once, and then a full dose. All I have read says you must take the same amount twice daily.
Sorry to get off track. I have felt lightheaded quite a bit, when out exercising. I have had all kinds of tests done for my ears, and my spine. Nothing. Then recently I read that a slow HR can result in dizziness. So now I am thinking, perhaps this is the reason. As with you, it seems that the Flecainide keeps the heart from speeding up. It is my thought that, yes it is the Flec that is causing your slow HR as well.
I am 61 and have been on 50mg bid flecainide for about a year. Before flecainide, I could run a half-marathon in 2:30 with HR at about 155. With flecainide, my sustainable HR dropped to 145, but my time improved to 2:20. I was able to train a bit harder too, since I wasnt nervous about popping into AF any more, so that might be a factor . I feel like the last few bpm at the top end arent really adding any performance, a bit like a car engine that makes max power somewhere below max rpm. I don’t take a beta blocker with the flecainide (cardiologist said ok), as I couldnt run at all with that.
This is a thread that I could usefully have read a while back when I took Flecanide regularly over a ren year period (I can’t now due to a NSTEMI and have since had an ablation but that’s a different story) - anyway to add to what seems to be the consensus; YES, I am confident Flecanide reduced my maximum HR and performance during exercise, but otherwise I think I tolerated it well and it kept AF at bay.
Many anti-arrhythmic medications have side-effects, Flecainide \ Bisoprolol may reduce the heart rate during exercise. Try not to overload your heart too much, warm up before and cool down afterwards. Listen to your body, and discuss any new exercise regimes with your Dr in advance. For further details, download the patient information sheet from the AF Association webpage: api.heartrhythmalliance.org...
If you have an irregular heart rate , atrial fibrillation, or flutter during exercise, it's likely that your HRM will not give an accurate read out, as it will tend to see that irregularity as errors. It may drop some readings, or "smooth" them as the Concept2 PM3 did.
A chest strap is better, but it depends how that information is processed by the HRM. It wasn't until I discussed it with the Concept2 technical people, that smoothing and error dropping came into the picture. A cardiac nurse once said to me that Polar HRMs were better with AF. I have a Polar Vantage V with a Polar H10 chest strap and transmitter. I pair the Bluetooth LE to the Vantage V, and ANT+ to the Concept2 PM5.
Hi Speed.I was researching the same thing. I am on flecainide about a year now and it definitely keeps my mx HR lower than what it was. I tend to get short of breath much quicker so battle with my workouts. But at least I can do them.
Have you had any other symptoms? I don't take any beta blockers.
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