The Doctor Is In: What You Should Know About Sudden Cardiac Death
By David Cannom
Event Date: 7/12/2001
Vice President Dick Cheney walked into the hospital on a Saturday and left the same day with a tiny implant near his left shoulder, programmed to save him from sudden cardiac death (SCD). What is sudden cardiac death? And what is this new device? Could it help you or someone you love? David S. Cannom, MD, FACC, will be in the WebMD Live Auditorium to answer your questions about SCD.
The opinions expressed herein are those of the guest's alone. If you have questions about your health, you should consult your personal physician. This event is meant for informational purposes only.
Moderator: Welcome to WebMD Live. Our guest today is Dr. David Cannom. He'll answer your questions about heart rhythms, sudden cardiac death, and procedures to maintain heart rhythm. You may ask a question at any time.
Moderator: Welcome to WebMD Live, Dr. Cannom.
Cannom: Thank you.
Moderator: Before we begin taking questions, can you please tell everyone a little bit about your background and area of expertise? I think everyone would like to know more about what an electrophysiologist does.
Cannom: I'd be happy to. My background and training is in cardiology at Stanford. Prior to that I had training in arrhythmia at the Staton Island Public Service Hospital. That was in the early days of clinical arrhythmia study and there were only 25 of us that were there over 7 years. Since then this has grown into a major component of cardiology with some 1,700 cardiologists practicing this specialty. The specialty deals with the study of complex electrical signals from the heart that can have serious health consequences if they are not treated properly, the most serious of which is sudden death. The other part of the specialty is cardiac pacing, which is delivery of electrical impulses to speed the heart up.
Moderator: Can you please discuss the recent procedure that Vice President Cheney underwent?
Cannom: Vice President Cheney underwent the implantation of what we call an implantable cardioveter defibrillator or ICD. The device that we are talking about is implanted in the heart by a lead system about the size of two long straws that are placed in the heart with the power pack placed under the skin in the left shoulder and about the size of a deck of cards. The device has now been in clinical use for 15 years and will deliver a shock to the heart if a lethal rhythm develops. It also has pacing backup if the heart rate gets too slow. The major function is to prevent a premature, unplanned arrhythmic death. These occur frequently in patients who have had prior heart attacks and have lost a substantial amount of ventricular muscle during their heart attack, as was the case with Cheney.
Moderator: Is it normal that someone can have the device implanted and leave the hospital the same day?
Cannom: Good question! The typical practice -- and we implant approximately 300 devices a year at our hospital -- is to keep the patient for at least a day after the implantation.
Moderator: How is the patient monitored following implantation?
Cannom: The patient is monitored on a cardiology ward with an arrhythmia detection system as well as careful attention to the wound over the device.
Moderator: How common is sudden cardiac death?
Cannom: Sudden cardiac death is one of the most important causes of mortality in the U.S. per year. The heart association estimates that approximately 250,000 people die suddenly each year in this country and are dying of a rapid electrical series of impulses. Once this attack begins it takes only some six or seven minutes until death ensues. It is during that time that ICD restores a normal rhythm; in fact, the restoration of normal rhythm takes about eight to 10 seconds. The leading cause of sudden cardiac death is coronary disease due to fatty deposits, and the first manifestation of heart disease is sudden death in about 50% of the patients who have heart trouble. The other patients who die suddenly already have known heart disease and have their fatal electrical impulse develop as a by-product of muscle scarring. It was to prevent such an episode that lead the George Washington physicians caring for Cheney to implant the ICD.
Moderator: How large are the devices? How long do they last?
Cannom: The devices that we implant are now about 40 cc and are as large as a deck of cards. They last, depending on how frequently they are used, about 8 years. At that point the battery is changed, which requires an operation. The lead system is used as long as it is functioning properly, which is usually a lifetime.