All parts of the body need a continuous supply of blood. For example, if the blood supply to the brain stops for longer than three minutes it becomes damaged. Other parts of the body can go without a blood supply for longer without being damaged. However, the muscular walls of the heart itself are quickly damaged if their blood supply is stopped.
Hospitals are always prepared for cardiac arrests. In a large hospital, there will usually be three or four doctors called the crash team. Their job is to get to any patient with a cardiac arrest as soon as possible. The problem is that hospitals are large, busy places. These doctors may be a long way from the patient. To overcome this, each member of the crash team carries a special bleep for emergencies. The bleeps are small radios which are tuned to a special transmitter at the hospital switchboard. There are telephones all over the hospital. If a patient has a cardiac arrest someone, usually a nurse, calls the switchboard. The switchboard operator presses a button and all the emergency bleeps make a loud bleeping noise. This noise can easily be heard by those who carry the bleeps. At the same time, the operator can tell the doctors, over the radio, where the patient is. The members of the crash team stop what they are doing. They go as quickly as possible to the cardiac arrest patient. When they arrive, they try to get the heart beating again. They may use drugs or a special electric shock machine. If these fail, an operation may be needed.