Respiratory cycle-dependent atrial tachycardia

Hi, I'm a fit 52yr old who was diagnosed with left atrial enlargement a few years back, suggested due to high cardio/endurance exercise. I now experience AF circa once every 2 or 3 weeks, always starts whilst sleeping and in the majority of cases I have reversed the next day via exercise. GP suggested beta blockers which I have refrained from taking until a follow-up with the cardiologist. I'm awaiting results from 24hr holder since I'm also suffering from slowly worsening what I believe to be respiratory cycle-dependent atrial tachycardia, but find little online info on this. Pending follow-up visit to cardiologist, I'd be interested to hear from anyone with experience of this condition and views on prevention/treatment. Thanks in advance, Brian

Respiratory cycle-dependent atrial tachycardia (RCAT) is very rare. What makes you think you're experiencing it?

If you are, the options for treatment are the same as for afib: drugs, ablation, or do nothing. It's actually a form of focal atrial tachycardia, so it's the same as afib originating from random individual locations in the atria. If you choose ablation, since you're also experiencing afib a PVI would be done first, and then the sources of focal activity would be mapped and ablated individually. That's actually standard procedure for any highly experienced EP even without an RCAT diagnosis, but I emphasize the word "experienced." This isn't afib for a lesser EP, and certainly not with cryo.

Being only 52, if I were in your shoes I would seek an ablation ASAP regardless of whether you have RCAT or not, and I would seek it only from a top EP.

Hi thanks for the reply. Like many I guess on this forum, I'm trying to get to grips with my condition and trying to leverage as much online resources as possible (with usual Dr Google caveat) until I get a full diagnosis. I'm a tad frustrated by what seems like a slow paced NHS here in the UK, but appreciate there are more pressing needs at times. RCAT was intimated by a cardiologist friend when I was describing my symptoms, and whilst there is limited info online, what I have found does resonate strongly. I have VERY marked heart rate difference between inhale and exhale, with tachycardia induced on inhale, ceasing abruptly on exhale, present pretty much every day now, and most marked lying down. I can also self-initiate same tachycardia through slow controlled inhalation almost at will. In your experience, does this sound like RCAT or maybe something else? Either way, I very much appreciate your feedback and suggestions and hope I can see a cardiologist soon and discuss options. Can I maybe check with you one thing however, why do you think an ablation ASAP given age? Thanks Brian

Well, what you describe sure sounds like RCAT. You might consider buying a Kardia to record it so you'll know for sure and you can show the cardiologist when you finally see one.

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briar
Can I maybe check with you one thing however, why do you think an ablation ASAP given age?

Because afib does one thing predictably: It progresses over time. At some point, your episodes will likely start becoming more frequent and lasting longer. The endpoint of that progression is persistent afib, which is extremely difficult to ablate. And since the old axim "afib begets afib" is true, the more you're in afib, the more often you'll experience it. You could potentially live another 40 years. That's a lot of time for afib to progress, to enlarge your atria, and to form more fibrosis. It's also a lot of time to spend on drugs with all sorts of side effects. Antiarrhythmic drugs have a tendency to eventually either quit working or to actually become proarrhythmic.

It's my opinion that as a general rule, the younger you are with afib, the more aggressive you need to be in treating it because there's simply nothing to be gained by waiting and significant things to lose.

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briar
Hi, I'm a fit 52yr old who was diagnosed with left atrial enlargement a few years back, suggested due to high cardio/endurance exercise. I now experience AF circa once every 2 or 3 weeks, always starts whilst sleeping and in the majority of cases I have reversed the next day via exercise. GP suggested beta blockers which I have refrained from taking until a follow-up with the cardiologist.

Briar, given your exercise history and the fact you can convert to NSR with exercise, you very likely have a vagal (vs adrenergic trigger). A chronic intake of a beta blocker will likely make the afib more frequent as it will increase your vagal tone. That being said, if you have high rates (>100 BPM) during your episodes, a BB as rate control during the episode would make sense.

Have you detrained at all? If not, the endurance exercise may be a trigger also.

George

Thanks both for your replies.

Carey - that makes sense and something I will bear in mind when seeing cardiologist. I will look into the Kardia since someone else mentioned that.

George - I've never totally detrained i.e. 3 months refrain from exercise, but do not train to the same frequency/intensity as I used to. I no longer.compete and then there is also then age/heart factor which has a bearing now anyway. I have a resting HR in the 50s and my Afib episodes are circa 80s (according to my Garmin which may not be 100% accurate). So not sure if beta blocker would help or not, but I will certainly be asking when seeing cardiologist.


If you both don't mind me asking a further question, and it is in relation to exercise, what's the general view on frequency/intensity and associated benefits/risks. is this something I should be inclined to reign back either in part of totally (or maybe detrain) or I've also read articles suggesting ramping it back up may benefit?

Thanks as always

Brian

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briar
I have a resting HR in the 50s and my Afib episodes are circa 80s (according to my Garmin which may not be 100% accurate). So not sure if beta blocker would help or not, but I will certainly be asking when seeing cardiologist.

If you both don't mind me asking a further question, and it is in relation to exercise, what's the general view on frequency/intensity and associated benefits/risks. is this something I should be inclined to reign back either in part of totally (or maybe detrain) or I've also read articles suggesting ramping it back up may benefit?

Hi Brian,

I can give you my opinion on exercise. Not sure all agree. I was 49 when I had my first afib episode. I was competing in high altitude races (one was 13 1/3 miles starting at 6300' and topping out at 14,100'). I'm now 64. My afib progressed rapidly. Initially ~6-9 hour episodes every 10-14 days which went to a 2.5 month episode starting 2 months after the initial episode. I proposed to my EP that he convert me and I'd try to stay in rhythm with electrolytes with on-demand (or pill in pocket) flecainide to convert me when I went out of rhythm. He agreed and this is what I've been doing since. My electrolytes are now magnesium to bowel tolerance, 2 tsp of potassium citrate powder with 1/2 tsp of table salt in a liter of water consumed over the day, 2-4 g of taurine powder/day and limiting calcium intake to around 600 mg/day.

It took me a while to realize I should detrain. In my case this meant not training (or competing) in endurance activities. I've noticed that, for me, it is the product of duration times intensity that is a trigger. So long duration, low intensity is OK as are high intensity short duration (like Tabatas) are OK. I've had a subjective sense as to how much is too much for me. For example, I can rock climb all day or alpine ski the steeps off piste all day. However, if I add hiking to gain elevation to every lap on the skiing, that is a trigger. I recently decided, I should add more volume and wanted to quantify what I'm doing. From the recommendation of a friend, Dr. Mark Cucuzzella, I decided to adopt Dr. Phil Maffetone's approach. In short, Maffetone suggests limiting your heart rate to 180-age, then trying to increase the amount of work you can do within that limit. Mark, who does a high volume of training, tells me he always wants to feel better when he comes back from training, not tired and exhausted. More details on Maffetone's method. One limit I've used for quite a while is to always exercise breathing through my nose, even at 12 or 13,000'.

This approach works for me. My electrolyte/detraining approach has been very successful. Currently, I've had 2 episodes in the last 18 months, being out of rhythm for a total of about 2 hours. I can be very active, but avoid the hard cardio that some of my friends do. I have a friend who loves to skin up and ski down. I don't do the skin up. I have friends who love doing century rides on their bikes. I don't do those. I will go out on a casual bike ride. Basically, I try to always be well within my capability. With Maffetone's approach, my heart rate limit is 116 BPM (180-64). I'm fit enough to push it to the 160's, and my max HR is 173, but I don't. Using this approach, I've been able to add more volume without any negative consequences in my afib.

Everyone will likely have to get a sense of what works for them. My approach may be too much for some, and some may be able to do a lot more without impacting their afib control.

Hope this helps.

George



Edited 2 time(s). Last edit at 12/08/2019 09:23AM by GeorgeN.

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GeorgeN

Hi, I'm a fit 52yr old who was diagnosed with left atrial enlargement a few years back, suggested due to high cardio/endurance exercise. I now experience AF circa once every 2 or 3 weeks, always starts whilst sleeping and in the majority of cases I have reversed the next day via exercise. GP suggested beta blockers which I have refrained from taking until a follow-up with the cardiologist.

Briar, given your exercise history and the fact you can convert to NSR with exercise, you very likely have a vagal (vs adrenergic trigger). A chronic intake of a beta blocker will likely make the afib more frequent as it will increase your vagal tone. That being said, if you have high rates (>100 BPM) during your episodes, a BB as rate control during the episode would make sense.

Have you detrained at all? If not, the endurance exercise may be a trigger also.

George

I agree here as far as the Beta-Blocker. Just take it when you have an AFIB episode. If you have Vagally-Mediated AFIB, it will probably make your condition worse. Common mistake Dr's make to the detriment of many.