A cardiac arrest is different from (but may be caused by) a myocardial infarction (also known as a heart attack), where blood flow to the muscle of the heart is impaired.[2] It is different from congestive heart failure, where circulation is substandard, but the heart is still pumping sufficient blood to sustain life.
Arrested blood circulation prevents delivery ofoxygen and glucose to the body. Lack of oxygen and glucose to the brain causes loss of consciousness, which then results inabnormal or absent breathing. Brain injury is likely to happen if cardiac arrest goes untreated for more than five minutes.[3][4][5]For the best chance of survival and neurological recovery immediate treatment is important.