You begin by opening the chest using a standard Y-shaped incision. After retracting the rib cage and opening the pericardium, you notice that the pericardial sac is distended with a red brown gelatinous substance.

What is this substance and how might it have gotten there?

Did this happen acutely or over time?

What is this phenomenon called?

Have you found your cause of death?

This is a case of cardiac tamponade, It is a complication of myocardial infarctions (MI) that occurs 3-7 days after a heart attack when the myocardial wall is weakened by a combination of coagulative necrosis and neutrophilic infiltration. The relative increase in pressure within the heart causes blood to burst through the wall and rush out into the pericardium. Because the pericardium is a closed space, only 200 mls of blood are required to constrict (or "tamp" down) the ventricular space, resulting in immediate death.