A heart attack occurs when the supply of blood and oxygen to an area of heart muscle is blocked, usually by a clot in a coronary artery. If treatment is not started quickly, the affected area of heart muscle begins to die. This injury to the heart muscle can lead to serious complications, and can even be fatal. Sudden death from heart attack is most often due to an arrhythmia (irregular heartbeat or rhythm) called ventricular fibrillation. If a person survives a heart attack, the injured area of the heart muscle is replaced by scar tissue. This weakens the pumping action of the heart and can lead to heart failure and other complications.
Effective treatments for heart attack are available that can decrease the chances of sudden death and long-term complications. To be most effective, these treatments must be given fast—within 1 hour of the start of heart attack symptoms. Acting fast can save your life and limit damage to your heart.
A heart attack is a life-threatening event. Everyone should know the warning signs of a heart attack and how to get emergency help. Many people suffer permanent damage to their hearts or die because they do not get help immediately.
Each year, more than a million persons in the United States have a heart attack, and about half (515,000) of them die. About one-half of those who die do so within 1 hour of the start of symptoms and before reaching the hospital.
Both men and women have heart attacks.
Emergency personnel can often stop arrhythmias with emergency cardiopulmonary resuscitation (CPR), defibrillation (electrical shock), and prompt advanced cardiac life support procedures. If care is sought soon enough, blood flow in the blocked artery can be restored in time to prevent permanent damage to the heart. Most people, however, do not seek medical care for 2 hours or more after symptoms begin. Many people wait 12 hours or longer.