A heart attack and cardiac arrest are two different medical emergencies related to the heart, but they have distinct differences: 1. Heart Attack: A heart attack, also known as myocardial infarction, occurs when there is a blockage in one or more of the coronary arteries. These arteries supply oxygen-rich blood to the heart muscle. The blockage usually occurs due to a blood clot forming in a narrowed or damaged artery. The heart muscle then becomes deprived of oxygen and begins to die. Symptoms of a heart attack may include chest pain or discomfort, shortness of breath, lightheadedness, nausea, and pain or discomfort in the upper body, such as the arms, jaw, neck, or back. 2. Cardiac Arrest: Cardiac arrest, on the other hand, is a sudden loss of heart function, causing the heart to stop beating. It can occur due to various reasons, including a heart attack, arrhythmias (abnormal heart rhythms), electrocution, drowning, or severe trauma. During cardiac arrest, the person loses consciousness, stops breathing, and there is no pulse. It is a life-threatening emergency that requires immediate intervention, such as cardiopulmonary resuscitation (CPR) and the use of a defibrillator to restore the heart's normal rhythm. In summary, a heart attack is caused by a blockage in the coronary arteries, while cardiac arrest is a sudden loss of heart function. A heart attack can lead to cardiac arrest, but not all heart attacks result in cardiac arrest.