- The Washington Times - Monday, March 19, 2001

Heart attacks afflict nearly a million Americans a year, but the number is expected to rise dramatically, and Vice President Richard B. Cheney is said to be partly responsible.
When the vice president admitted himself to George Washington University Hospital two weeks ago, doctors initially declared he had not experienced a heart attack.
They said the pain that motivated him to seek help was caused solely by sharply reduced blood flow to the heart caused by failure of a tiny tubular implant, or "stent," intended to keep a damaged artery open.
Later, after performing a new test, doctors altered the finding. They said Mr. Cheney had, indeed, experienced his fourth heart attack, or "myocardial infarction," based on the new test.
Mr. Cheney's condition, along with the widespread publicity he has received as well as the belated recognition of his heart attack, have focused attention on a recent and important alteration in the way doctors test for and diagnose such episodes.
As a result of the new test, University of Michigan researchers say they expect some 250,000 or 26 percent more heart attacks will be reported each year. They also told the annual meeting of the American College of Cardiology yesterday that the test will affect patient treatment and treatment costs, although no one knows how much.
In an interview, the research-team leader, Dr. Rajendra Mehta, said that without the new test those 250,000 "myocardial infarctions would have been missed." And as his team's analysis shows, the undiagnosed attacks would likely have resulted in less vigorous therapy, subsequent severe heart attacks and even death.
Dr. Mehta explained that until last fall physicians based their diagnoses of heart attack on criteria established by the World Health Organization. The criteria dictated that a heart attack has occurred if the victim evidences any two of three conditions: decreased blood flow to the heart, critical changes in an electrocardiogram or elevated enzymes.
Enzymes are proteins that trigger changes in cells, and enzymes in heart cells are vital they help to keep the organ beating. Yet until September 2000 when a joint committee of the European Heart Society and the American College of Cardiology introduced new guidelines, it wasn't necessary to test for elevated enzymes if the other two criteria were met.
The new guidelines stipulate that suspected heart attack patients should be tested for elevated enzymes plus one of the other two criteria. What's more, the guidelines include the option of testing for one specific enzyme called troponin.
"This is the first definition published that officially includes the use of troponin as a diagnostic marker," Dr. Mehta states.
That's significant because troponin is plentiful in heart cells but is not found in other tissue and is not present in the blood of healthy people. So finding it in an individual's blood means it has leaked from a traumatized heart.
The Michigan researchers based their findings on a study of 493 patients admitted to the University of Michigan Health System with suspected acute coronary syndrome. They identified 305 patients with elevated enzyme levels and then divided those patients into two groups.
One group contained patients with high levels of an enzyme called CKMB, which is the enzyme commonly checked under WHO criteria when doctors actually opt to test for enzyme levels. Those people were diagnosed as having had a heart attack. They received aggressive therapy.
The other group had normal CKMB levels, but high troponin. Using the old criteria, doctors would have said the hearts of patients in that group had gone unscathed. And they would have been wrong.
Said Dr. Mehta, "We already know that inadvertent missed diagnoses of heart attack may have grave consequences, including death. Using troponin levels allows us to identify more high-risk patients and give them the care they need."


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