A heart attack, also called a myocardial infarction (MI), happens when blood flow to the heart is blocked. It is usually triggered by the rupture of plaque buildup inside a coronary artery. This causes a clot, which can then block the artery. When the artery is blocked, the area of the heart it supplies is deprived of blood and oxygen. That part of the heart begins to die.

When heart muscle dies, the damage is permanent. Early treatment can reduce or reverse the amount of damage the heart muscle suffers. Minutes count! And I mean that literally. For anyone having a heart attack, immediate medical attention is critical for two reasons:

1. Most of the damage done by a heart attack occurs during the first few hours. Treatment given during that time can help avoid permanent heart muscle damage.

2. Cardiac arrest, a sudden loss of heart function due to an abnormal heartbeat, is a danger during the first few hours of a heart attack. Without a defibrillator to shock the heart, death occurs in minutes.

Despite what many people think, heart attack and cardiac arrest are not the same thing. A heart attack refers to the death of heart muscle tissue due to loss of blood supply. Cardiac arrest, which can be brought on by a heart attack, is the total loss of heart function due to electrical malfunction of the heart.

When the heart stops, blood doesn’t flow to the brain or the rest of the body. A person will collapse, lose consciousness, and stop breathing. The American Heart Association reports that every year, about 335,000 Americans die from cardiac arrest before they can get to the hospital.