Oct. 15, 2008

News reports indicate Vice President Dick Cheney will visit George Washington University Hospital on Wednesday after doctors discovered a recurrence of an abnormal heart rhythm.

Doctors say Cheney was “experiencing a recurrence of atrial fibrillation, an abnormal rhythm involving the upper chambers of the heart,” said a Cheney spokesperson. He will undergo an outpatient procedure to restore his normal rhythm.

The American Heart Association’s patient web site, http://www.HeartHub.org, has tools and resources for people looking for information on atrial fibrillation and other forms of arrhythmias.

Link to information on Internal Cardioverter Defibrillators:
http://americanheart.org/presenter.jhtml?identifier=558

Information on surgical techniques to treat arrhythmias:
http://americanheart.org/presenter.jhtml?identifier=6

Information about arrhythmias:
http://www.hearthub.org/hc-arrhythmia.htm
 

Background information from the American Heart Association regarding Vice President Dick Cheney’s heart procedure

What is Atrial fibrillation?
Sometimes the heart’s electrical signals can lose their regular pattern. In the condition called atrial fibrillation (AF), many parts of the atria, the heart's two upper chambers, send uncoordinated electrical signals. The atria pump too fast and unevenly and won't fully contract. In fact, they may contract 5–7 times faster than normal — up to 300–400 beats per minute. Not all of these signals go to the lower chambers (ventricles), so although their rate is irregular, it won't be this fast and the ventricles can still pump out blood.

An estimated 2.2 million Americans are living with AF. That makes it the most common “serious” heart rhythm abnormality.

AF isn't life-threatening, but it can lead to other rhythm problems, chronic fatigue, congestive heart failure and, worst of all, stroke. When your left atrium pumps too fast and unevenly, blood doesn't empty completely into your left ventricle. Instead, leftover blood "pools" in the atrium. This blood can form clots. If a clot breaks loose, enters the bloodstream and travels to the brain, it can plug an artery and cause a stroke. This doesn't happen to everyone with AF, but your chances of having a stroke are five times higher if you have AF. About 15–20 percent of all strokes occur in people with AF.

What is an implantable cardioverter defibrillator?
An implantable cardioverter defibrillator is used in patients at risk from recurrent, sustained ventricular tachycardia or fibrillation.

The device is connected to leads positioned inside the heart or on its surface. These leads are used to deliver electrical shocks, sense the cardiac rhythm and sometimes pace the heart, as needed. The various leads are tunneled to a pulse generator, which is implanted in a pouch beneath the skin of the chest or abdomen. These generators are typically a little larger than a wallet and have electronics that automatically monitor and treat heart rhythms recognized as abnormal. Newer devices are smaller and have simpler lead systems. They can be installed through blood vessels, eliminating the need for open chest surgery.

When an implantable cardioverter defibrillator detects ventricular tachycardia or fibrillation, it shocks the heart to restore the normal rhythm. New devices also provide overdrive pacing to electrically convert a sustained ventricular tachycardia, and "backup" pacing if bradycardia occurs. They also offer a host of other sophisticated functions (such as storage of detected arrhythmic events and the ability to do “noninvasive” electrophysiologic testing.

Implantable cardioverter defibrillators have been very useful in preventing sudden death in patients with known, sustained ventricular tachycardia or fibrillation. Studies are now being done to find out how best to use them and whether they may have a role in preventing cardiac arrest in high-risk patients who haven't had, but are at risk for, life-threatening ventricular arrhythmias.

According to the American Heart Association Heart and Stroke Statistical Update, in 2005 (the most recent statistics available) there were 91,000 ICD procedures.

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