DETROIT - As many as a third of Americans who get implantable defibrillators to correct heartbeat irregularities may not need them, a finding that could lead to as much as $690 million in Medicare savings, a University of Michigan Medical Center study says.
Better answers of who is a candidate for a defibrillator implant may come from a test that provides precise information on how well the heart pumps blood, the study found. But more research must be conducted before it is widely accepted as a screening tool, said Dr. Paul Chan, senior author of the study.
The report was published in the January issue of the Journal of the American College of Cardiology.
The test, known as MTWA, for microvolt T-wave alternans, measures changes in calcium levels in the heart, Chan said. It costs about $400 and is conducted much like a treadmill stress test, only less vigorously. Other tests are conducted to determine whether a patient needs a defibrillator but can be more invasive or provide less information.
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A defibrillator is a small device implanted in the chest to correct an abnormal heartbeat.
Medicare has paid for the MTWA test for about a year but many other plans do not, one reason its use has not become more widespread, said Dr. Timothy Shinn, an electrophysiologist at the Michigan Heart and Vascular Institute at St. Joseph Mercy Hospital.
St. Joseph has been involved with national studies of the MTWA test. There, patients are offered the test if they have various risks, including an enlarged heart, Shinn said.
Elsewhere the test is not widely offered. The University of Michigan Medical Center does not offer the test, according to Chan. Neither does Detroit's St. John Hospital & Medical Center, a leading cardiology hospital.
Dr. Sohail Hassan, an electrophysiologist at St. John, said the MTWA test eventually will be used earlier to screen patients before they have a heart attack.