Fibrosing cardiomyopathy is a disease commonly caused by a heart failure in great apes, most specially the males. When fibrosing cardiomyopathy attacks a healthy heart, it comes with a bacterium or a virus that makes the muscles of the heart turn into fibrous bands which makes them unable to pump blood in the blood streams. When a gorilla is stressed, or the food it eats, then catecholamine which is a harmful substance is released in the heart muscle that make the C-reactive protein that is found in blood plasma produced by the liver to swell, causing rheumatoid arthritis.