Snake heart: a case of atavism in a human being.

Atavism is the rare reappearance, in a modern organism, of a trait from a distant evolutionary ancestor. We describe an apparent case of atavism involving a 59-year-old man with chest pain whose coronary circulation and myocardial architecture resembled those of the reptilian heart. The chest pain was attributed to a coronary steal phenomenon. The patient was discharged from the hospital on a heightened regimen of β-blockers, and his symptoms improved significantly. To our knowledge, this is only the 2nd reported clinical case of a human coronary circulation similar to that of reptiles.