Symptoms

Signs of sudden cardiac arrest are immediate and drastic and include:

• Sudden collapse
• No pulse
• No breathing
• Loss of consciousness

Sometimes other signs and symptoms occur before sudden cardiac arrest. These might include:

• Chest discomfort
• Shortness of breath
• Weakness
• Fast-beating, fluttering or pounding heart (palpitations)

But sudden cardiac arrest often occurs with no warning.

When to see a doctor

Call 911 or emergency medical help if you experience any of these signs and symptoms:

• Chest pain or discomfort
• Heart palpitations
• Rapid or irregular heartbeats
• Unexplained wheezing
• Shortness of breath
• Fainting or near fainting
• Lightheadedness or dizziness

When the heart stops, the lack of oxygen-rich blood can cause death or permanent brain damage within minutes. Time is critical when you're helping an unconscious person who isn't breathing.

If you see someone who's unconscious and not breathing normally, do the following:

• Call 911 or emergency medical help. f you have immediate access to a telephone, call before beginning CPR.

• Perform CPR. Quickly check the person's breathing. If the person isn't breathing normally, begin CPR. Push hard and fast on the person's chest — at the rate of 100 to 120 compressions a minute. If you've been trained in CPR, check the person's airway and deliver rescue breaths after every 30 compressions.

  If you haven't been trained, just continue chest compressions. Allow the chest to rise completely between compressions. Keep doing this until a portable defibrillator is available or emergency workers arrive.

• Use a portable defibrillator, if one is available. It will give you step-by-step voice instructions. Continue chest compressions while the defibrillator is charging. When it's charged, the defibrillator will check the person's heart rhythm and recommend a shock if needed. Deliver one shock if advised by the device and then immediately resume CPR, starting with chest compressions, or give chest compressions only, for about two minutes.

  Using the defibrillator, check the person's heart rhythm. If necessary, the defibrillator will give another shock. Repeat this cycle until the person recovers consciousness or emergency workers take over.

Portable automated external defibrillators (AEDs) are available in many places, including airports, casinos and shopping malls. You can also purchase one for your home. AEDs come with built-in instructions for their use. They're programmed to allow a shock only when appropriate.