The day Vice President Richard Cheney received his ICD was a step forward in the care of people who have survived a prior heart attack. The ICD, which stands for "implantable cardioverter defibrillator," is a pacemaker-like device. Doctors called it an "insurance policy" for the Vice President - it was there if he needed it. And, because of the type of heart disease Mr. Cheney has, it's likely that someday he will need his ICD to protect him from dying suddenly from cardiac arrest (also called "sudden cardiac death" or SCD). SCD is almost always caused by ventricular fibrillation (VF), a dangerous heart rhythm disorder. In VF, the heart suddenly and without warning begins to beat too fast, quiver and spasm. When this happens, the heart no longer can pump blood to the body. Mr. Cheney, like millions of other Americans, is a heart attack survivor. According to reports, he has a damaged heart, although it does not appear to interfere with his normal lifestyle. Preventing Heart Attacks Until the Vice President received his ICD, most of the information about his health focused on preventing further heart attacks. That meant a good exercise program, losing weight, watching his fat intake, and medications that control his cholesterol and, if necessary, his blood pressure. But his cardiologists were aware of a lingering problem that these treatments could not prevent - patients who suffer heart attacks may be at high risk for sudden death due to a heart rhythm disorder that leads to VF. Physicians who are concerned with preventing heart attacks or caring for patients with heart failure or other disorders caused by a damaged heart, often do not give as much thought to the risk of sudden cardiac death. Sudden cardiac death often is misunderstood by patients,and frequently even by physicians. It can occur in hearts that are literally "too good" to die. Often, the problem is an "electrical storm" coming from the scar of a previous heart attack. Like sticking your hand in a light socket, the electrical activity from this scar causes the heart to go into spasm, preventing it from pumping. When that happens, the heart stops and, unless emergency help is available within minutes, the patient dies. It is important to know that this heart spasm can be converted back to a normal heartbeat with a controlled, electrical shock. Most Americans have seen a defibrillator on ER. Two large paddles are placed across the victim's chest, everyone is told to stand clear, and the device discharges electrical energy that restores the patient's heartbeat. Now it is possible to implant a similar device that is about the size of three, stacked silver dollars with wires leading into the heart. An ICD performs the same function as the large defibrillator. Sudden cardiac death is a common problem for patients who have had heart attacks. In fact, it is responsible for at least half the deaths after a heart attack. The other deaths occur from another heart attack or from heart failure. The impact of the defibrillator that Mr. Cheney has cuts his risk for sudden death from one in ten to one in a hundred. The question patients and their families ask after a heart attack is, "Do I need one of those devices that Cheney had"? The answer is, "perhaps." The question was addressed by several clinical trials on patients who survived a significant heart attack. These patients were monitored and those with abnormal heart rhythms underwent special testing to determine whether or not they were at risk for sudden death. If they were, they were either given medication or received an implantable defibrillator. At the end of five years of study, researchers determined that the group of patients with implantable defibrillators had nearly a 50 percent reduction in their death rate. If you've had a heart attack and have a significant amount of damage, you may be at risk for sudden death. You need to find out how much damage you have. The way we measure that is with a number called the ejection fraction (EF). This number is the percentage of blood pumped with each beat. Normally, we should pump out 50 percent or more of the blood in our heart with each beat. In a damaged heart that is at risk for cardiac arrest, that number drops to 35 percent or below. So you should ask your doctor how much damage you have and ask, "What is my ejection fraction?" If it is abnormally low, you may be referred to a heart rhythm specialist called an electrophysiologist who will monitor your heart to see if you show signs of an abnormal heart rhythm. Like Mr. Cheney, you may feel fine and carry on a vigorous lifestyle but still have a heart that is potentially at risk for ventricular fibrillation and sudden cardiac death. If you don't know your EF, check it out. It could save your life.