Blue dye, green heart

Methylene blue has been used for the rapid reversal of circulatory shock refractory to fluid administration, inotropic agents, and vasoconstrictors. Its clinical side effects have been well described. We report an interesting autopsy observation in patients who received methylene blue as adjunct therapy for septic shock. The exposed surface of cardiac myocardium on both fresh and fixed states rapidly turned green. In the presence of molecular oxygen, the colorless metabolite leukomethylene blue is readily oxidized to methylene blue, thus explaining the visible color change of the myocardium.