During cardiac arrest, a person’s heart stops beating. Cardiac arrest isn't the same thing as a heart attack, but it’s worth discussing alongside a heart attack. Cardiac arrest can occur due to a heart attack, but cardiac arrest can also be a primary event. In other words, cardiac arrest can also occur for other reasons besides a blockage in the coronary artery. These other reasons include electrolyte disturbances such as low or high potassium or low magnesium, congenital abnormalities, valve disease, electrical disorders, scar tissue, or poor heart pumping function.
In a heart attack, a person’s heart keeps beating. A heart attack can cause life-threatening arrhythmias (abnormal heart rhythms) like ventricular tachycardia (VT) or ventricular fibrillation (VF). These arrhythmias result in a cardiac arrest within a few minutes because the heart is not pumping blood to the lungs to pick up vital oxygen that circulates back to the heart and the body.
Seconds count in treating both heart attack and cardiac arrest. With cardiac arrest, the odds of survival go down by about 10% for every minute until the person is resuscitated. After 10 minutes, the risk of permanent brain injury is very high.
Initial treatment will consist of cardiopulmonary resuscitation (CPR), defibrillation, and electrical shock delivery to restore the heart’s rhythm. For people who are resuscitated and have a heartbeat but do not regain consciousness, hypothermia protocols are sometimes used, where the body is cooled for 24 hours and then gradually warmed. This has been shown to improve the odds of a good neurological outcome for those patients.