Cocaine does only a few things to the heart that can be dangerous or cause death.
Cocaine can temporarily reduce the amount of oxygen being supplied to an area of the heart muscle.
Either way, the blood supply to a section of heart muscle would be decreased or stopped completely. The length of interruption of blood supply to the heart muscle determines how badly the heart muscle will be injured. A short interruption is usually accompanied by chest pain that lasts only a short time. Except for cocaine users, it is usually seen only in people over 45, and mostly in those 60 years old and older. If the interruption lasts too long, heart muscle cells die from lack of blood and oxygen.