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Running head: ATRIAL FIBRILLATION IN ATHLETES
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Atrial Fibrillation in Athletes
Tammie Brueckner, PAS-2
Nova Southeastern University
College of Health Care Sciences
Physician Assistant Department-Jacksonville
Master of Medical Science
PAJ 6370: Clinical Elective Rotation 1, Cardiology
Professor Bolton
Elective “Clinical Brief”
Due February 2, 2015
ATRIAL FIBRILLATION IN ATHLETES
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Atrial Fibrillation in Athletes
Introduction
Atrial fibrillation (AF) is the most common sustained supraventricular tachyarrhythmia,
and a clear direct association with age exists especially after the seventh decade of life (Andreoli,
Benjamin, Griggs, & Wing, 2010). The presence of AF is detectible by some patients who may
complain of palpitations, shortness of breath, fatigue, reduced exercise capacity or dizziness, and
a thorough cardiac evaluation should be performed to determine an underlying or precipitating
cause (Cheng & Kumar, 2014). In the general population typical risk factors for AF include
hypertension and coronary heart disease, but it is important to remember that AF is caused by a
change in the electrophysiology of the atrial myocardium; in athletes, recent evidence suggests
that increased parasympathetic tone, reduced sympathetic tone and increased inflammation puts
this subset of the population at risk for AF (Sorokin, Araujo, Zweibel, & Thompson, 2011).
Atrial Fibrillation
Epidemiology. Atrial fibrillation affects approximately 9% of individuals over 80 years
of age and often appears paroxysmally over a period of time before it becomes the established
rhythm (Papadakis & McPhee, 2014). In adults less than 55 years old, the prevalence drops to
less than 0.1% and appears to be more common in Caucasian men (Cheng & Kumar, 2014). The
incidence of AF also increases with advancing age and with underlying cardiovascular diseases.
According to the Framingham study, men ages 40 to 95 have a 26% risk of developing AF, and a
23% risk from ages 80 to 95, which illustrates how AF incidence arises with age (Cheng &
Kumar, 2014).
Pathogenesis and Diagnosis. Atrial tachycardia (AT) occurs at rates between 100-250
beats per minute due to an ectopic focus that is firing at a rate faster than the sinus rate (Andreoli
ATRIAL FIBRILLATION IN ATHLETES
et al., 2010). Atrial flutter (AFl) occurs with a reentry impulse in the right atrium, which
passively activates the left atrium. According to Moe’s hypothesis, atrial fibrillation is
maintained by having a critical number of wavelets circulating the atria and result in ineffective
atrial contraction. Many times during AF, impulses are blocked at the atrioventricular (AV)
node resulting in an irregular ventricular rhythm taking over. An electrocardiogram for AT and
AFl will show unique P-wave morphologies, while AF will show no distinct P-wave activity
(Andreoli et al., 2010).
A thorough history and physical can elucidate the presence of active AF, but with
intermittent episodes the application of a Holter Monitor or even a continuous loop recorder can
aid in the diagnosis (Cheng & Kumar, 2014). Sometimes AF can be found incidentally in
healthy patients who have a CHADS2 score of zero, meaning that they have no comorbidities
and a low risk of ischemic stroke; this type of AF where there is an absence of structural heart
disease is termed lone AF (Cheng & Kumar, 2014; Li, Zhang, Scherlag, & Po, 2010).
Treatment. The American Heart Association (AHA) sets guidelines for diagnosing and
treating AF with the goal of lowering the risk of consequences such as stroke or myocardial
infarction. Treatment options vary with each patient and are outside the scope of this article.
Exercise
The AHA (2015) suggests at least 150 minutes per week of moderate activity or 75
minutes per week of vigorous activity, or thirty minutes a day, or a combination of both. Adults
who follow this regimen are less likely die of heart disease and stroke, which are the nation’s
number 1 and number 5 causes of death. To lower blood pressure or cholesterol, AHA
recommends 40 minutes of aerobic exercise like walking, jogging swimming or biking.
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Athletes. Competitors often train at levels much more intense and for periods much
greater than recommended by the AHA, and with constant strain the heart goes through stages of
remodeling (Li et al., 2010). It is important for athletes to pay attention to any symptoms that
may indicate the presence of AF, discussed previously in this article.
Discussion
It is widely accepted that regular aerobic exercise reduces cardiovascular risk (Li et al.,
2010). Many health care providers harp on the importance of exercise and diet, but many
patients hear this without listening. While exercise seems to be avoided at all costs by much of
the population, other people take it to the extreme. Athletes push their bodies to limits, and with
the help of medicine, supplements and determination, they overcome obstacles to reach their
goals. There are many side effects of too much exercise, from injuries to death, but one thing
that most athletes and their healthcare providers often overlook is their susceptibility to atrial
fibrillation. There appears to be a consensus that no exercise and high intensity exercise may
lead to AF, and recommendations lean toward low to moderate intensity exercise to reduce the
incidence of AF (Li et al., 2010).
Taking age into account, elderly people can reduce their risk of AF by participating in
moderate physical activities; however if their cumulative lifetime hours are longer than 1500, the
incidence of AF increased (Li et al., 2010). Marathon runners who practiced more than 3 hours
weekly for more than 2 years also had a higher incidence of AF (Li et al., 2010). Even more
interesting is a study that showed mortality is much lower in a group of elite athletes than their
sedentary control group, but the incidence of AF was much higher (Sorokin et al., 2009).
The relationship between the cardiac autonomic nervous system and AF suggests that
atrial stretch in a dilated atrium can induce AF by providing a place for reentry of the impulse
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(Po et al., 2010). Another study showed excessive exercise raised the C-reactive protein level,
which is also elevated in AF patients (Sorokin et al., 2009).
Conclusion
While exercise can be used to improve overall cardiovascular health, excess activity may
actually lead to AF (Sorokin et al.,). Due to changes in the electrophysiology of the atrial
myocardium, which can be produced through strenuous and long term exercise, AF can occur
during an athlete’s prime or later in life at a higher incidence than people who exercise at
moderate levels (Po et al.,).
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References
American Heart Assocation recommendations for physical activity in adults, 2015.
(http://www.heart.org/HEARTORG/GettingHealthy/PhysicalActivity/FitnessBasics/Ame
rican-Heart-Association-Recommendations-for-Physical-Activity-inAdults_UCM_307976_Article.jsp)
Andreoli, T., Benjamin, I., Griggs, R., Wing, E. (Ed.). (2010). Andreoli and Carpenter's CECIL
Essentials of Medicine (8 ed.). Philadelphia PA: Saunders Elsevier.
Cheng, A., Kumar, K. (2014). Overview of Atrial Fibrillation. In G.M. Saperia (Ed.),
UpToDate. Retrieved from http://www.uptodate.com/home
Li, S., Zhang, Z., Scherlag, B., & Po, S. (2010). Atrial fibrillation in athletes - the story behind
the running hearts. Journal of Atrial Fibrillation, 1(11), 626-629.
Papadakis, M., McPhee, S. (Ed.). (2014). Current Medical Diagnosis & Treatment (53rd ed.).
New York NY: McGraw Hill.
Sakabi, K., Fukuda, N., Soeki, T., Shinohara, H., Tamura, Y., & Wakatsuki, T. (2003). Relation
of age and sex to atrial electrophysical properties in patients with no history of atrial
fibrillation. Cardiology and Clinical Research, 26(3), 1238-1244.
Sorokin, A. V., Araujo, C. G., Zweibel, S., & Thompson, P. D. (2011). Atrial fibrillation in
endurance-trained athletes. British Journal of Sports Medicine, 45(3), 185-188.
American Heart Assocation recommendations for physical activity in adults
(http://www.heart.org/HEARTORG/GettingHealthy/PhysicalActivity/FitnessBasics/Ame
rican-Heart-Association-Recommendations-for-Physical-Activity-inAdults_UCM_307976_Article.jsp)