What is Cardiac Arrest?

The American Heart Association defines cardiac arrest as an abrupt loss of heart function. The victim loses consciousness, breathing stops, and there is no pulse. If blood flow isn’t restored within just a few minutes, usually defined as 4 to 6 minutes, the victim’s chances for survival are not good.The most common cause of cardiac arrest is coronary artery disease, which reduces blood flow through the arteries that supply the heart muscle. The term “heart attack” refers to an event in which a portion of heart tissue receives no blood and the tissue begins to die. The medical term for this is "myocardial infarction." Each year 250,000 deaths are attributed to heart attack and about half of these – more than 680 people each day – are the result of coronary artery disease.

In many cases of coronary artery disease, there are symptoms – usually chest pain -- before the blockage in one or more vessels is sufficient to cause a heart attack. 

But in many cases, there are no warning signs that could alert you to seek early medical attention. In these cases, the heart attack is the first symptom and cardiac arrest may occur as part of, or within minutes of, the first heart attack symptom. 

Heart attack isn’t the only cause of cardiac arrest, however, and it is important to understand that cardiac arrest may occur in association with other problems. For example, when there is a disruption of the electrical impulses that produce each heart beat, the resulting irregularities may cause the heart rate to be too slow, too fast, or too chaotic to maintain blood flow to the body. Cardiac arrest may occur when these irregularities are not quickly reversed, because the heart must receive a continuous supply of blood just as the rest of the body and all vital organs depend on the heart to pump blood effectively. 

Other problems that can result in cardiac arrest include respiratory arrest, electrocution, drowning, choking, and trauma. Cardiac arrest is also known to occur without any known cause.

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