Anyone else on the forum suffer from atrial fibrillation or heart palpitations? I had a few episodes in my 20s but then no problems until 2009 when I was 47. At that time I spoke to a cardiologist who ran a few tests and diagnosed lone atrial fibrillation which apparently is quite common in older athletes. Anyhow he prescribed flecainide acetate or the “pill in the pocket” to be taken in the event of an AF episode. Until quite recently I had barely used the medication, finding that the heart rhythm usually reverted to normal status within a few minutes. However more recently I experienced several episodes of AF whilst actually on the bike, usually occurring in the recovery phase immediately after completing a hard effort. For example cresting a hill during a road race the AF might kick in whilst soft pedalling down the other side. This entails stopping to take the medication and then waiting for it to take effect which obviously means the end of my race. A complete pita. I’ve re-scheduled another visit to the cardiologist but I strongly suspect he’s going to suggest using the flecainide proactively, ie taking a small dose each day, rather than reactively in response to an episode of AF.

I think this is the same condition that affected Sean Yates in the latter part of his career and also one of the current Spanish pros whose name escapes me presently. Anyhow, any informed comments would be greatly appreciated, especially from anyone in a similar situation who races and takes Flecainide as a routine dose. I would be interested to hear the effects such medication has on maximum heart rate and power output. Ta.

Hi Liam,
How well does it work compared to just stopping and not taking the pill. I ask because when considering paroxysmal AFib there are a couple of potential endogenous triggers. It tends to occur because of either vagal stimulation or adrenergic stimulation. In the event where the trigger is hard efforts, in races in particular, the adrenergic stimulation seems the most likely cause and this generally does not respond well to flecainide. Generally in this case a Beta Blocker works best. No reason you couldn't do a pill in pocket type strategy with a short acting Beta Blocker.

In regards to performance effects of flecainide or Beta Blockers the news isn't great. I would not be as worried about dropping your heart rate with flecainide as the fact that it decreases contractility, stroke volume and ejection fraction of the heart. Essentially when taking the med the heart does not pump as much blood with each stroke, as you can imagine this is not good for a cyclist. Beta Blockers generally are the opposite they are bad for rate and response of the heart rate to stressors so it doesn't rise as much, again not good for cyclists.

I am assuming your cardiologist ruled out structural issues in the heart before starting as this is a dangerous contraindication. I would also be concerned about daily flecainide here as low potassium increases risk of arrhythmias and I do always worry about medications effected by hypokalemia when riding aggressively in hot weather.

My other question is do we know this is a fib versus PSVT or just sinus tachycardia? How was this captured during exercise, Holter, Loop monitor?

I am not a cardiologist but take interest in cyclists. If it was me I would ask the cardiologist about seeing the EP to determine if radiofrequency ablation is a possibility as in the case of a competing cyclist a drug free solution would seem best.

I have copied an excellent though fairly in depth and jargon rich link about Paroxysmal afib: http://qjmed.oxfordjournals.org/content/94/12/665.full" onclick="window.open(this.href);return false;

drchull, very many thanks for your comprehensive reply and the also the journal link.

My initial episodes of afib were fairly random, perhaps sitting watching tv or working in the office and they only lasted a short time, perhaps 10 minutes at most. These incidents usually converted to normal rhythm unaided or else by implementing some form of manoeuvre, for example taking a deep breath and holding for a few seconds or even simply bending forward, both of which have worked for me. I don’t recall ever taking the flecainide for these non-cycling related incidents. However those episodes that occur whilst on the bike, and I have to say they are becoming a little more frequent now, or shortly after finishing do appear considerably more pronounced and persistent, causing me to take the Flecainide almost immediately. I must admit I do find these cycling related incidents fairly frightening probably due to the fact that my heart rate is already high and with the onset of afib the Garmin goes a tad off the scale! I’ve recorded a pulse rate of 230+ during one episode which completely freaked me out, considering that my training max is 192!! In addition, during these episodes I have found that my at-rest “manoeuvres” are completely in-effective, hence I take the flecainide right away. Usually the cycling related events will revert to normal rhythm with 30-40 minutes.

I understand your suggestion that the most likely trigger is adrenergic stimulation but I do wonder if, for me, there is a possible element of vagal stimulation. For as long as I can remember I’ve had minor, but persistent, digestive issues such as wind and bloating. These were investigated in my 20s but nothing adverse was found and no real conclusions were reached. However I do know that my afib episodes quite frequently occur during those periods when my digestive issues are more pronounced and I do wonder if there may be some correlation. Certainly I have sometimes noticed that the resolution of my afib attacks is accompanied by a large tummy burp.

I was fitted with a Holter over a weekend period and, despite completely thrashing myself on the bike for two days, no afib was recorded. Sod’s law! The cardiologist also undertook an ECG and an ultra sound examination and he seemed assured that there were no structural issues involved.

With regard to any medication is there a certain degree of trial and error involved in finding a compromise between controlling the afib without unduly impairing performance on the bike? Or maybe I’m being naïve in thinking such a compromise can ideally be achieved. As you suggested ablation may be the best solution for a competing cyclist. My understanding is that, although ablation techniques have greatly improved in the last number of years, the procedure is not a guaranteed success but it is definitely an avenue I would be keen and prepared to explore. But then again would NHS funding stretch to what could possibly be viewed as a non-essential ablation to satisfy the whims of an aging bike racer?!

Apologies for the long post and thanks again for your considerations.

Liam