A heart attack and a cardiac arrest are both serious medical conditions that occur when the heart stops working properly. However, they are not the same thing. A heart attack occurs when the blood supply to part of the heart is blocked, causing damage to the heart muscle. Symptoms of a heart attack can include chest pain, shortness of breath, and nausea. A cardiac arrest, on the other hand, occurs when the heart suddenly stops beating. This can be caused by a heart attack, but it can also be caused by other medical conditions. Symptoms of a cardiac arrest include loss of consciousness, no pulse, and no breathing. Treatment for a heart attack usually involves medications to restore blood flow to the heart, while treatment for a cardiac arrest typically requires CPR and defibrillation.