Email a Friend
Print ArticleHeart Health Center
This article is from the WebMD News Archive
Test Predicts Cardiac Death Risk
Nov. 15, 2006 (Chicago) -- A noninvasive test that uses computer technology to gauge whether a person is at risk of sudden cardiac death can help doctors determine who will benefit from implanted defibrillators, researchers report.
In a study of more than 500 people who had some history of heart damage, the test was just as accurate as the more invasive electrophysiological screen now in use, says David S. Rosenbaum, MD, professor of medicine at Case Western Reserve University in Cleveland.
But unlike standard electrophysiological screening, the new test "is noninvasive, safe, and relatively inexpensive," he tells WebMD. "That makes it much more suitable as a screening tool to apply to a large population."
The study was presented at the annual meeting of the American Heart Association (AHA).
Sudden Cardiac Death Leading Killer
Sudden cardiac death is a leading cause of natural death in the U.S., taking the lives of about 325,000 adults each year.
Sudden cardiac death occurs when the electrical system to the heart malfunctions. This can cause a dangerously abnormal heart rhythm. The victim can lose consciousness and death can occur unless emergency treatment is begun immediately.
People at high risk of sudden cardiac death due to a heart attack or other cardiac damage are often fitted with implanted cardioverter defibrillators (ICDs). The ICD monitors a person's heart rate and rhythm. If the heartbeat becomes abnormal, ICDs deliver an electrical jolt, shocking the heart back to normal rhythm.
Testing the Old Way
One way to determine who will benefit from a defibrillator is to look at a person's ejection fraction -- a measure of the heart's pumping abilities.
"But that strategy is inadequate," Rosenbaum says. He estimates that more than nine in 10 people who get an ICD based on ejection fractions never develop erratic heartbeats that need a shock.
"Based on ejection fraction alone, one has to implant about 17 defibrillators to save one life. Clearly better diagnostic strategies are needed," he says.
The new test, known as the microvolt T wave alternans (MTWA), measures an electrical discharge called the T wave on an electrocardiogram. It is a marker for irregular heart rhythms that can cause sudden cardiac death.
A computer program analyzes subtle differences in a person's T-waves from one beat to the next, thereby giving individualized risk information.
del.icio.us
What’s the number one killer of women? Heart Disease. A campaign is under way to teach women that heart disease isn’t just for men.
