A heart attack and a cardiac arrest are two serious medical conditions, but they are not the same. A heart attack occurs when the blood flow to the heart is blocked, usually by a buildup of plaque in the arteries. The lack of blood flow can cause significant damage to the heart muscle, which can lead to chest pain, shortness of breath, and even death. A cardiac arrest is a sudden loss of heart function, usually caused by an electrical problem with the heart. It causes the heart to stop beating, leading to unconsciousness and death unless emergency medical attention is given.