A Rare Presentation of Probable Training-Related Chronic Myopericarditis in an Endurance Cyclist: A Case Report.

We report a rare case of high-volume training-related myopericarditis. A male, 18 years old, elite road bicycle racing cyclist with high-volume training of 1,000 km per week for >7 years, presented with progressively worsening exertional breathlessness, reduced effort tolerance, and one episode of cardiac syncope. The symptoms were present prior to the coronavirus disease 2019 pandemic but made worse with the sudden increase in the volume of training after lockdown periods in preparation for competition. He exhibited multiple premature ventricular ectopic beats during his resting electrocardiogram, with a normal echocardiogram and non-elevated cardiac enzyme. The exercise stress test revealed similar multiple premature ventricular beats, warranting further investigation using cardiac magnetic resonance imaging (MRI). The findings of the cardiac MRI were suggestive of myopericarditis. He was instructed to refrain from training and initially started with a short course of colchicine. However, his symptoms deteriorated, and cardiac MRI revealed a decrease in the left ventricular ejection fraction from 59% to 50%. His treatment was escalated to a short course of tapered dose steroid, anti-failure medication and gradual, supervised, return to sports program. This case report highlights the discussion of return to play in athletes with myopericarditis.