Working Diagnosis:
Atrial Fibrillation with controlled ventricular response in the absence of rate slowing agents

Treatment:
Electrical Cardioversion

Outcome:
He had a successful cardioversion with 150J shock two days after presentation. He underwent a treadmill stress test ten days after cardioversion and reached 94% of maximum HR predicted for age, with no ST changes, arrhythmias, or symptoms. Repeat ECG's ten days and one month after cardioversion showed normal sinus rhythm. Once diagnosed with atrial fibrillation, he was held out of all physical activity including football and weightlifting. He was allowed to return to full activity four days after successful electrical cardioversion, and has maintained sinus rhythm to date

Author's Comments:
We still are unsure of the cause of his atrial fibrillation.

He was cardioverted electrically instead of chemically because he could be in and out of the hospital with electrical cardioversion, while with chemical he would have to be watched for approximately 48 hours as many of the chemical agents are pro-arrhythmic.

The stress test after cardioversion was done to ensure his atrial fibrillation wasn't related to exertion and wouldn't recur when he went back to football.

A TTE was done to look at his valves as another possible cause of his atrial fibrillation. A TEE wasn't done because his CHAD score was zero. A TEE would normally be done if he was high risk for a clot or >60yo.

Atrial fibrillation can be intiated by vagal or adrenergic predominance in young healthy athletes. Vagally induced AF usually occurs at night, in the immediate hours after intense exercise, or after heavy meals. Adrenergically induced AF usually starts during the daytime and can be provoked by exercise, caffeine, or stress.

It seems the risk of atrial fibrillation in athletes is higher than in non-athletes. This is possibly explained by the increased vagal tone with subsequent bradycardia that may lead to dispersion of atrial repolarization, increasing susceptibility to AF.

References:
1) Hoogsteen J, Schep G, et al. Paroxysmal atrial fibrillation in male endurance athletes. A 9-year follow up. Europace 2004; 6: 222-228.
2) Abdulla J, Rokkedal Nielsen J. Is the risk of atrial fibrillation higher in athletes than in the general population? A systematic review and meta-analysis. Europace 2009; 11: 1156-1159.
3) Sorokin AV, Araujo CGS, et al. Atrial fibrillation in endurance-trained athletes. BJSM 2010.

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