Recognizing the warning signs of a heart attack or sudden cardiac arrest, which takes the lives of more than 325,000 Americans each year, and getting help within the first few minutes of someone becoming ill can save the person's life. Although sudden cardiac arrest (SCA) is often confused with a heart attack (myocardial infraction), the two events are different. A heart attack occurs when one or more of the arteries sending blood to the heart are blocked and oxygen can't reach the heart muscle and the muscle becomes damaged. Sudden cardiac arrest is caused by an "electrical problem" in the heart when the heart's lower ventricles (chambers) suddenly develop a fast, irregular rhythm (ventricular fibrillation) causing the ventricles to quiver instead of contracting, cutting off oxygen to the body and the brain. The result is loss of consciousness and a pulse within seconds.

Although both heart events are medical emergencies requiring immediate attention, patients with sudden cardiac arrest only have a few minutes to live unless treatment is started right away, so getting help quickly is imperative.

Know the Warning Signs

Some heart attacks come on suddenly, but most of the time they start slowly. Here's how to tell if a heart attack is happening:

  • Chest Discomfort-Most heart attacks involve pain in the middle of the chest that lasts more than few minutes, or that goes away and comes back later.
  • Pain in the Upper Body-In addition to the chest, heart attack symptoms can include discomfort in one or both arms, the back, neck, jaw or stomach.
  • Shortness of Breath-With or without chest pain.
  • Other Symptoms-Breaking out in a cold sweat, nausea or lightheadedness.

Even if you're not sure if you or someone you know is having a heart attack, it's better to be safe than sorry. The American Heart Association recommends not waiting longer than five minutes before calling 911 or your local emergency number for help.

Sudden cardiac arrest comes on suddenly and without warning. Here's how to tell if someone is in SCA:

  • There's a sudden loss of responsiveness
  • The patient has no normal breathing when you tilt her head up for at least five seconds

If you see the signs of SCA, call 911 immediately and use an automatic external defibrillator (AED) to jolt the patient's heart rhythm back to a normal heartbeat. If you don't have an AED, begin cardiopulmonary resuscitation (CPR) until emergency medical care workers arrive.