According to the American Heart Association, about 250,000 Americans die annually of coronary heart disease before they ever get to the hospital. That's more than 680 people each day. Most of these deaths are caused by cardiac arrest.

"This accounts for more deaths yearly than stroke, AIDS, and lung and breast cancer combined," says Jeffrey Rothfeld, MD, FACC, a cardiologist at Manatee Memorial Hospital. "Someone who goes into cardiac arrest outside of a hospital has only a 5 percent chance -- or less -- of survival."

About 80 to 90 percent of the cardiac arrests that lead to sudden death occur when the electrical impulses in the heart become rapid (ventricular tachycardia), chaotic (ventricular fibrillation) or both. This irregular heart rhythm (arrhythmia) causes the heart to quiver unproductively instead of pumping blood. Some cardiac arrests are due to extreme slowing of the heart, called bradycardia.

Different than a heart attack
Cardiac arrest is not the same thing as a heart attack. A heart attack refers to damage caused to heart muscle tissue when a clot blocks its blood supply. It does not necessarily result in a cardiac arrest or the death of the heart attack victim. A heart attack may cause cardiac arrest, but the terms are not synonymous.

Timing is everything
When a person goes into cardiac arrest, an emergency responder must deliver an electric shock to the heart with a cardiac defibrillator. This resets the heart to its normal rhythm.

"The sooner the defibrillation is given the better," says Dr. Rothfeld. "If defibrillation is provided within the first five minutes of a cardiac arrest, you have about a 50-50 chance of saving the victim's life. But with each passing minute, the survival rate falls by about 10 percent. So after only 10 minutes there's very little chance of successful rescue."

That's why cardiologists try to identify patients who are most at risk for sudden cardiac death. "You wish you could have EMTs with defibs follow these patients around all the time. Of course, that's not possible, so our next best option is to implant a pacemaker or an internal cardiac defibrillator," says Dr. Rothfeld.

Jeffrey Rothfeld, MD, FACC Bradenton Cardiology 316 Manatee Ave. West Bradenton, FL 34205 941-748-2277

Implantable devices
A pacemaker is designed to help patients with abnormally slow heart rates. "It's about the size of two half-dollars stacked," says Dr. Rothfeld. "It's the most common implantable device." Pacemakers deliver consistent electrical impulses to keep the heart beating at the correct pace.

An internal cardiac defibrillator (ICD) is about the size of a beeper and weighs about two to three ounces. The ICD continuously monitors the heart, recognizes certain types of abnormal heart rhythms (arrhythmias) and delivers a single shock to restore the heart to its normal rhythm. Some new ICDs are combination devices that also function as pacemakers.

Resume living your life
The surgery usually requires a onenight hospital stay. "After the device is implanted, patients are encouraged to resume their normal activities shortly after the procedure," says Dr. Rothfeld. Contrary to popular thinking, a person with an ICD or pacemaker can use cellular phones, microwave ovens and go through the metal detectors at airports and security devices at retail stores. No activity is restricted afterwards. "I had one patient who had a terribly weak heart, but now he does Taebo and is a champion windsurfer," says Dr. Rothfeld.