The epicardial surface of the heart shows a shaggy fibrinous exudate. This is another example of fibrinous pericarditis. This appearance has often been called a "bread and butter" pericarditis, but you would have to drop your buttered bread on the carpet to really get this effect. The fibrin often results in the the finding on physical examination of a "friction rub" as the strands of fibrin on epicardium and pericardium rub against each other.