Red Sox manager Terry Francona has either myocarditis or pericarditis
“Red Sox manager Terry Francona was released from a hospital Friday, two days after experiencing chest pains that doctors said were likely caused by a virus.

Francona complained of tightness in his chest and was hospitalized in New York on Wednesday before the Red Sox played the Yankees. He later was transferred to Massachusetts General Hospital in Boston for more testing.

Team physician Dr. Thomas Gill said Friday that tests showed no evidence of a serious heart problem and that Francona’s chest pains probably were caused by ‘a recent viral illness.'”

He had a pretty thorough evaluation, including a cardiac catheterization. He was already on blood thinners and an IVC filter, making a pulmonary embolus unlikely.

Pericarditis and myocarditis are frequently associated with viruses. With myocarditis, the true diagnosis is made via an endomyocardial biopsy – but this is normally considered if there are severe heart symptoms (heart failure or arrhythmia),

There is no specific treatment for myocarditis – although studies are looking at antiviral medication. Close followup is recommended, with slow advancement of physical activity. This is probably why the doctors are so careful in letting Francona back on the field.