cycling and AF - Speece's question

[Michael Burke]

I forwarded Speece's question from last week about "returning to normal" after a bout of exercise-induced AF to my buddy Walter Mashman, who is a cyclist and also the director of sports cardiology at Piedmont Hospital.  His response is below:

Hi guys,

 

I'll probably regret this, but here we go. I’ll paraphrase your question as follows: What is the success rate of de-conditioning in returning the heart to normal after AF?

 

I’ll answer with a series of concepts that will not satisfy you, but might add some insight. For starters, we have to remember that the heart is pliable, and “remodels” based on the hemodynamic forces to which it is subjected. With regard to chamber dimension and hypertrophy, there is “negative remodeling” (unfavorable) and “positive remodeling” (favorable). An athletic heart generally remodels in ways that are favorable (better at delivering output) for the situation, but there can be problems. A return to “normal” can be measured clinically (recurrence of AF or not), structurally (chamber dimensions can be measured), or theoretically (fibrosis could be seen microscopically after you’ve died). With extreme athleticism, there may be “permanent damage” to the heart. That can be seen with myocardial fibrosis, coronary dysfunction (atherosclerosis, calcification, endothelial dysfunction), etc. This is a complex topic, and the answer is “does it matter”? Will it impact quality of life (level of function/symptoms/need for healthcare attention, etc) or prognosis?

 

Exercise improves overall prognosis. The risk of most cancers (except skin) is lower in people who exercise. Cardiovascular pathology (which kills most people) prognosis is improved with exercise until the extreme. There is a “c-curve” such that with extreme exercise over long term, some of the overall benefit is lost. (This is a very interesting area of study. Why is the prognostic benefit of exercise lost in the extreme? Too broad to discuss here). As you know, AF is significantly more likely in older endurance male athletes.

 

AF is very common in the general population. It is different in different people. Those people who have had AF are at higher risk of having it again. People don’t generally die from AF directly, but it can be a real pain in the butt, and in higher-risk populations does increase the risk of stroke. It can decrease performance, and sometimes may require procedures or medications. As we consider our commitment to fitness, we should frame the concern about AF in the context of our individual goals. Consider quantity of life (prognosis), and quality of life. My personal opinion is that cycling greatly improves both, despite the risks.

 

I hope this is helpful, although I’m pretty sure I did not answer your question. I would be happy to try to answer other questions if they arise. Please be as specific as possible. 

Walter

Walter Mashman, MD, FACC, FASE

Piedmont Heart Institute

Director of Sports Cardiology, Piedmont Healthcare

275 Collier Road | Suite 500 | Atlanta, GA 30309 USA

404.605.2800

walter....@piedmont.org

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Michael Burke

404 271 8652

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