THURSDAY, Nov. 1, 2007 (HealthDay News) -- A simple test can give cardiologists guidance about whether they should implant defibrillators into patients with weak hearts, new research confirms.
Implanted defibrillators aren't necessary for all patients and can be extremely expensive, noted Dr. Paul Chan, a cardiologist at Mid-America Heart Institute in Kansas City who's familiar with the study findings.
"Not all patients with weak heart muscle are made alike," Chan said. "There's growing evidence that this test may help determine who is at higher risk and who may be at low risk for sudden cardiac risk. And who may be the best candidates to receive -- or not receive -- a defibrillator."
At issue are patients whose heart muscles are weak and may be at especially high risk of dying suddenly. Some have a condition known as heart failure, which can be extremely debilitating, while others may appear perfectly healthy.
"We have people who are in their 50s and 60s, and if they don't have symptoms, they can do everything in their lives that we all do," Chan said. "They can climb stairs, they can have jobs and don't have any apparent symptoms. [But] some get short of breath after 4 to 5 blocks of walking or even after a half-block of walking."
The new study was led by Dr. Jorge Salerno-Uniarte, of the Ospedale di Circolo e Fondazione Macchi, Varese, Italy. His team looked at the medical records of 446 cardiac patients who underwent a test known as T-wave alternans. It's similar to a traditional stress test and requires patients to exercise enough to boost their pulse to 120 beats a minute, Chan said. Electrical leads, meanwhile, measure how their hearts function.
The study is published in the Nov. 6 issue of the Journal of the American College of Cardiology.
The researchers found that those who had abnormal test results were more than four times more likely to suffer abnormal heart rhythms or die within 18 to 24 months of the test.
Those who received normal scores on the test had "a very good prognosis and are likely to benefit little" from having defibrillators implanted, the study authors wrote.
It may seem to make sense to simply install defibrillators in anyone who's at a higher-than-normal risk of cardiac death. The machines, after all, are designed to keep people alive by shocking the heart into a normal rhythm when it is in danger of not beating due to an electrical disruption.
But by one estimate, 17 defibrillators need to be implanted in order for one to save a single life. And, according to Chan, it can cost $40,000 to implant one of the little machines.
In addition, defibrillators don't make patients feel better on a day-to-day basis, Chan said. "It doesn't make your symptoms any better or make you walk longer or climb a stairs without being short of breath. The only thing it prevents is sudden death from cardiac arrhythmia."
More information
For more on sudden cardiac death, visit the American Heart Association.
