Cardiac Arrest


What is cardiac arrest?


Cardiac arrest is the abrupt loss of heart function in a person who may or may not have been diagnosed with heart disease. It can come on suddenly, or in the wake of other symptoms. Cardiac arrest is often fatal, if appropriate steps aren’t taken immediately.


Each year in the United States, more than 350,000 cardiac arrests occur outside of a hospital setting.


Is a heart attack the same as cardiac arrest?


No. The term “heart attack” is often mistakenly used to describe cardiac arrest. While a heart attack may cause cardiac arrest, the two terms don’t mean the same thing.


Heart attacks are caused by a blockage that stops blood flow to the heart. A heart attack (or myocardial infarction) refers to death of heart muscle tissue due to the loss of blood supply. Heart attack can be understood as a “circulation” problem. A heart attack is quite serious, sometimes fatal.


By contrast, cardiac arrest is caused when the heart’s electrical system malfunctions. The heart stops beating properly. Hence the name: The heart’s pumping function is “arrested,” or stopped.


In cardiac arrest, death can result quickly if proper steps aren’t taken immediately. Cardiac arrest may be reversed if CPR (cardiopulmonary resuscitation) is performed and a defibrillator is used to shock the heart and restore a normal heart rhythm within a few minutes.


Cardiac arrest may be caused by irregular heart rhythms, called arrhythmias. A common arrhythmia associated with cardiac arrest is ventricular fibrillation. Ventricular fibrillation means that the heart’s lower chambers suddenly start beating chaotically and don’t pump blood.


Causes of Cardiac Arrest


Cardiac arrest may be caused by almost any known heart condition.


Most cardiac arrests occur when a diseased heart’s electrical system malfunctions. This malfunction causes an abnormal heart rhythm such as ventricular tachycardia or ventricular fibrillation. Some cardiac arrests are also caused by extreme slowing of the heart’s rhythm (bradycardia).


Irregular heartbeats such as these that can cause cardiac arrest should be considered life-threatening arrhythmias.


Other causes of cardiac arrest include:

  • Scarring of the heart tissue Such scarring may be the result of a prior heart attack or another cause. A heart that’s scarred or enlarged from any cause is prone to develop life-threatening ventricular arrhythmias. The first six months after a heart attack represents a particularly high-risk period for sudden cardiac arrest in patients with atherosclerotic heart disease.