Sudden Cardiac Death (Cardiac Arrest)

Sudden cardiac death (SCD), also called cardiac arrest, is used to describe a situation in which the heart abruptly and without warning stops working, so no blood can be pumped to the rest of the body. It is responsible for half of all heart disease deaths.

Sudden cardiac death occurs when the heart’s electrical system malfunctions. It is not a heart attack (also known as a myocardial infarcation). A heart attack is when a blockage in a blood vessel interrupts the flow of oxygen-rich blood to the heart, causing heart muscle to die. So if the heart can be compared to a house, SCD occurs when there is an electrical problem and a heart attack – when the problem is the plumbing.

The most common cause of cardiac arrest is a heart rhythm disorder or arrhythmia called ventricular fibrillation (VF). The heart has a built-in electrical system. In a healthy heart, a "pace- maker" triggers the heartbeat, then electrical impulses run along pathways in the heart, causing it to contract in a regular, rhythmic way. When a con- traction happens, blood is pumped. But in ventricular fibrillation, the elec- trical signals that control the pumping of the heart suddenly become rapid and chaotic. As a result, the lower chambers of the heart, the ventricles, begin to quiver (fibrillate) instead of contract, and they can no longer pump blood from the heart to the rest of the body. If blood cannot flow to the brain, it becomes starved of oxygen, and the person loses consciousness in seconds. Unless an emergency shock is delivered to the heart to restore its regular rhythm, using a machine called a defibrillator, death can occur within minutes. It’s estimated that more than 70% of ventricular fibrillation victims die before reaching the hospital.

Cardiopulmonary resuscitation and advanced cardiac life support are not always in a person's best interest. This is particularly true in the case of terminal illnesses when resuscitation will not alter the outcome of the disease. Properly performed CPR often fractures the rib cage, especially in older patients or those suffering from osteoporosis. Defibrillation, especially repeated several times as called for by ACLS protocols, may also cause electrical burns. Internal cardiac massage, an ACLS procedure performed by emergency medicine physicians requires splitting open the rib cage, which is painful during the weeks of recovery. While such treatment is worthwhile when it saves a life, it is sometimes perceived as undignified and adding to the suffering of a victim with a terminal illness who wishes to die peacefully.

Some people with a terminal illness choose to avoid such measures and die peacefully.

People with views on the treatment they wish to receive in the event of a cardiac arrest should discuss these views with both their doctor and with their family.

It is also important that these views are written down somewhere in the medical record. In the event of cardiac arrest, health professionals need to act quickly on the information that is available to them. As cardiac arrest often happens out of regular hours, the resuscitation team rarely includes anybody who actually knows the patient.

A patient may ask their doctor to record a do not resuscitate (DNR) order in the medical record. Alternatively, in many jurisdictions, a person may formally state their wishes in an "advance directive" or "advance health directive".