Sorry, bro, not his heart exploding. The arguments would be that either (1) he's off anticoagulants and with an underlying hypercoagulable condition developes a blood clot somewhere in his body that, because of physical activity, arguably gets dislodged and goes into his pulmonary circulation or (2) he's on an anticoagulant and people are concerned that he suffers a type of trauma on the basketball court that causes internal bleeding.
Both of the above could happen off the court and, in fact, would be a more likely scenario, at least in terms of the former.
