Ablation and nine months later, PACs

[Rpoole8537]

Nine months ago I came here discuss my six hour ablation procedure after I developed persistent and pervasive afib and a flutter. For four months I had to take Tikosyn in the hopes of shutting diminishing the chances that the neural pathways would recreate. It was a tough medicine to take, but I was hopeful that it might be a good strategy. About three weeks ago, while taking easy rides in rolling hills I noticed strange readings on my heartrate monitor. I would be cruising along in the low 90's and suddenly it would drop to 53. Now it will also get stuck on say, 108 and just remain there for as long as 30 seconds while I coast down a hill. My doctor thinks it is PAC, or premature atrial contractions. I do not feel a loss of power, but it is worrisome. The doctor is sending a holster monitor to wear during exercise. Any opinions or ideas or suggestions? Thanks

[biker72]

If you're not losing any power it could very well be PAC's.
See what results the Holter monitor shows.

I'm not a doctor but have had similar problems.

[numbskull]

You are asymptomatic so I would not get too worried here.

The same process that causes atrial fibrillation often makes people prone to electrical irritability that results in premature beats. Exercise can magnify these, although this is often in midrange exercise and recovery......often as the HR increases people over-ride the extra beats. APBs themselves do not typically cause problems with limitation of exercise tolerance (although they drive some people nuts at rest because of increased cardiac awareness which is actually more a GI issue.....but that is a whole 'nother story)

The ablation procedure itself causes electrical irritation and scarring which often results in atrial irritability. This can take the form of extra beats (APBs) , runs of left atrial ectopic tachycardia (perhaps the "stuck" HR of 108), or episodes of faster left atrial flutter (the more common right atrial flutter circuit is usually eliminated as part of the original procedure). Anything that stimulates the heart tends to increase the automaticity of these arrhythmias. They often diminish with time although some people remain on anti-arrhythmic or beta-blocker therapy long term, and sometimes they go back in to try and ablate the irritative focus itself (which is a different procedure than the original AF ablation).

It also may help to understand that for many patients AF is not the disease itself, but rather a symptom or reflection of a wider "problem" (better considered as premature aging, perhaps) of the heart's electrical tissues. The ablation may eliminate the AF but other electrical abnormalities such as HR slowing (or blunted HR response to exercise), extra beats, or conduction slowing often persist or develop with time. When you go through a 6 hour procedure it is natural to hope you are "cured" but the reality is often that you have been "improved" rather than cured.

You would do well not to focus too hard on the HR monitor but rather concentrate on how you feel. If you are pedaling hard and feel strong what your heart rate is doing is really unimportant. It is far more important what your heart is doing at rest since uncontrolled tachycardia at rest can lead to problems over time and asymptomatic arrhythmia such as AFL or AF can increase stroke risk if you are not anti-coagulated.

[Md3000]

Don't trust the hr monitor. It's made to give you an indication of heart rate while exercising but not to accurately monitor specific heart issues. The drops to 53, I've had similar readings and usually they are pvc's that are real fast but the hr monitor measures them incorrect, for example hr 53 turned out to be a short 212 bpm pvc (ie. 4x as fast as the measurement). But like I said, get accurate measurements.
regardless of numbers - first question your doctor will ask is: are u out of breath / feel winded / chest pain or tightness.

[HenryA]

No claim to medical knowledge here, but don't rely on a bicycling heart rate monitor. The real monitor the doctor gives you will give readings with high confidence for figuring out what's going on.

[Rpoole8537]

Earlier in the week, I began taking 250 mg of magnesium twice a day. This morning I rode a casual ride for about 1.5 hours. It was 80 degrees but very humid. After one week of taking magnesium, my HR was much more steady, especially after warming up a bit. Also, it would go up and down consistent with my effort. I hear the message from you guys and my doctor not to be too concerned, but when you've been to the ER three times because of afib, you tend to be on guard. Thanks to Numbskull for the detailed analysis and conclusion. That is a more in depth response than my cardiologist, who I think is a good doctor. My resting HR is very good, high 50's to low 60's. I'm 60 yo and have been running and/or riding since 1980. I do understand that I am improved, not cured. And I accept that, I have no choice. I have tried to make other changes such as less caffeine, alcohol and stress. One question, is 500 mg of magnesium too much?
I do appreciate the feedback and support from this group.

[Md3000]

Two other things you could look into are Taurine (for energy) and L-Carnitine. With a lot of supplements; no cardiologist will prescribe them but there are plenty indications that they are beneficial.

[2LeftCleats]

Could be simply a faulty HRM. My Polar would often get stuck at a particular HR, no matter my effort. Or suddenly shoot up to >200 with no change in workload. Since I switched to a Garmin, it's been much more accurate.

[gasman]

500 mg of magnesium is not too much and it could help your cardiac irregularities some.

[CNY rider]

Earlier in the week, I began taking 250 mg of magnesium twice a day. This morning I rode a casual ride for about 1.5 hours. It was 80 degrees but very humid. After one week of taking magnesium, my HR was much more steady, especially after warming up a bit. Also, it would go up and down consistent with my effort. I hear the message from you guys and my doctor not to be too concerned, but when you've been to the ER three times because of afib, you tend to be on guard. Thanks to Numbskull for the detailed analysis and conclusion. That is a more in depth response than my cardiologist, who I think is a good doctor. My resting HR is very good, high 50's to low 60's. I'm 60 yo and have been running and/or riding since 1980. I do understand that I am improved, not cured. And I accept that, I have no choice. I have tried to make other changes such as less caffeine, alcohol and stress. One question, is 500 mg of magnesium too much?
I do appreciate the feedback and support from this group.

You'll know you are taking too much magnesium when you get diarrhea.

[mistermo]

I'm sorry, I'm not going to be much help. I had an ablation in February that went well. I was told that the choice of doctor and skill level is very important. I researched and found a good doc. My procedure went well and I've had no recurrences. My suggestion would be to find a good doc and ignore the advice offered on a cycling forum. Which, of course, includes this advice.

[rnhood]

I had an ablation in 2010 which was entirely successful, with my heart subsequently beating like a clock and no restrictions on exercise. Believe me, I run it to the rail. In the sixth year, which was about a year ago, I started getting PVC's from time to time. They can be felt so if you are not feeling them, chances are its the monitor. Jerseys or jersey static are(is) known for interfering with the Garmin units or straps. You might want ride without the jersey and see what happens.

Even so, PAC/PVC's are typically totally benign. If you do not have any underlying anomalies, the docs almost always write it off as benign unless you are having over 20k skipped beats per day (20% of your hearts daily beats are PAC/PVC). That's a lot.

Having said this, a-fib, PVC, PAC, and any other heart anomaly is very individualized and there is certainly no one-size-fits-all resolution. But if you had an ablation, then I can assure you that your doctor knows if your heart has any underlying conditions or anomalies as part of their homework and preparation maps or models the heart very well.

[Rpoole8537]

Thanks Mhood. Yes, every heart is different. I was getting the same result from three different monitors. Riding without a jersey might be a good idea. When my heartrate was dropping to 53, I could feel the skipped beat by feeling my pulse at the base of my neck. My doctor studied at Duke and Emory and has a great reputation in Upstate SC. Still, the skill of operating the catheter is different from excelling in the classroom. He is also a marathon runner, so he knows a bit about exercise and HR. Best news, the magnesium seems to be helping to manage my HR much better after only four or five days of taking it. I'm more optimistic than four days ago.


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