Fifty years ago, if a person had a heart attack, physicians could not do much for the patient. He or she would survive or not, depending on the severity of the attack. If a person had a sudden cardiac arrest, where the heart is no longer pumping blood because its rhythms become abnormal and fibrillate, or quiver, the person would usually die. We now have many tools to help us diagnose and treat cardiac emergencies, and some of the most helpful emergency treatments are cardiopulmonary resuscitation consisting of rhythmic chest compressions, and the use of defibrillators.

Defibrillators have been in use in hospitals for several decades. Nurses and doctors monitor a person's electrical rhythm of the heart and watch for abnormal patterns. If a patient's heart begins to fibrillate, they can shock the heart, with the hopes of interrupting the lethal rhythm, allowing a more normal one to resume. Then, the heart can effectively pump blood. More recently, technology has progressed, and we have portable defibrillators that are easy to use.

Automated external defibrillators are portable electronic devices that can diagnose if an unconscious person is having an abnormal life-threatening electrical heart rhythm. It can occur because of a heart attack, a sudden heart rhythm problem, a drug overdose or other cause. Since these chaotic heart rhythms do not allow the heart to pump blood to the brain and other body organs, the victim will be unconscious, stop breathing and have no pulse.

The only way to stop these rhythms and reset the heart to beat normally is with a defibrillator. Hence, if the heart is quivering (fibrillating), it needs to be de-fibrillated, so we shock the heart. Since the AEDs are programmed to recognize only certain kinds of dangerous heart rhythms, it will not shock a normal rhythm. The longer a person's heart is in these abnormal rhythms, the lower his or her chances of survival.

AEDs are now more commonly found in public places and the average person can save a life in the mall, in a school or in the airport. Using CPR immediately can help maintain blood pressure and flow. This is important to attempt to keep the bodies organs oxygenated by providing blood flow to them. However, it is very important to restore an effective heart rhythm as soon as possible, through the use of an AED. Survival rates are higher with early defibrillation. With an AED, anyone can turn on the device and follow the voice instructions that come from the machine. It will instruct the person on what to do each step of the way from that point on including when to stop and restart CPR. Of course, call 9-1-1 to get the emergency responders to the scene.

According to the American Heart Association, 294,851 of EMS calls are for cardiac arrest and 80 percent of these are in private residences. If more people are trained in CPR, which now includes training on how to use an AED, this can mean the difference between life and death for a person in distress. The American Heart Association and the American Red Cross program include AED training in their CPR courses.

Beth McGee is a Nurse Practitioner and Hospitalist at St. Patrick Hospital and Health Sciences Center.