A 67-year-old homeless man is brought

to the emergency department by ambulance. He was found unresponsive by the

police. Despite appropriate first aid and immediate transport to the

hospital, he dies. Examination of the heart during autopsy shows normal size

and shape. A photomicrograph of a section of the heart obtained at

autopsy is shown. How does the amount of substance indicated by the arrow

relate to the person´s age?