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Cardiac arrest

A cardiac arrest which is also called clinical death is an absence of systole: that is, the failure of the ventricless of the heart to contract. Cardiac arrest is a life-threatening medical emergency that will lead to true death within minutes.

Table of contents
1 Causes
2 Diagnosis
3 First aid
4 Field care (for EMTs)
5 Clinical treatment
6 Cardiac arrest and do not resuscitate (DNR)


In healthy adults, cardiac arrest is often caused by ventricular fibrillation during a heart attack. The resultant lack of blood supply results in cell death from oxygen starvation and to the death of the individual if resuscitation procedures are not carried out within minutes.

In children, cardiac arrest is typically caused by hypoxia from other causes such as near-drowning. With prompt treatment survival rates are high.

Every fatal injury or illness ultimately terminates in cardiac arrest, which is a natural part of the processes of death.


The state of cardiac arrest has the nickname, flatline because on an electrocardiogram (EKG), the lack of electrical activity in the heart is indicated by a flat horizontal line. (A normal EKG would show three peaks in the line corresponding with electrical activity associated with each heartbeat.)

First aid

Call for help immediately; preferably, send someone else to do so. Seconds count. Cardiopulmonary resuscitation ("CPR") should be given immediately. CPR only buys time for advanced responders to arrive; it does not restart the heart. If an automated external defibrillator (AED) is available, apply it to the patient at once and follow the instructions on the device.

Field care (for EMTs)

Apply advanced cardiac life support protocols. However, check for an do not resuscitate (DNR) order. If a valid DNR order signed by a physician or an advance directive form supported by your local protocols is present and applies to the patient, do not apply advanced cardiac life support but permit natural death to occur in accordance with the wishes of the patient.

Clinical treatment

In the hospital setting where a do not resuscitate (DNR) order has not been made, announce "Code Blue" for immediate response by the nursing staff and a physician trained in emergency medicine. Apply advanced cardiac life support protocols. Continue until the patient recovers or death is declared by a doctor.

Cardiac arrest and do not resuscitate (DNR)

In cases where a person is dying due to terminal illness, they may choose to avoid heroic measures and die peacefully. To make this wish known, the patient will ask their doctor for a do not resuscitate (DNR) order which prevents advanced cardiac life support from being used if the patient goes into cardiac arrest.

Properly performed, cardiopulmonary resuscitation will injure or even fracture the rib cage. Defibrillation, especially repeated several times as called for by ACLS protocols, will cause electrical burns. Direct cardiac massage, an ACLS procedure performed by a physician in emergency medicine, requires splitting open the rib cage, which is excruciatingly painful during the weeks of recovery required. All of this is justifiable when done to save life. It amounts to torture if the victim wants to die peacefully.

This advance denial of consent to initiate resuscitation, called in some jurisdications an "advance directive", is usually initiated by the person with the terminal illness when resuscitation will not alter the outcome of the disease. See also death and hospice.