MRI can be used to locate tissue damage in a heart attack or pinpoint blockages, but it has not been used to predict heart attacks.
"This study is the first to determine that MRI is a strong prognostic forecaster," says lead author W. Gregory Hundley, a cardiologist and associate professor of internal medicine and radiology at the Wake Forest University School of Medicine in Winston-Salem, N.C. "Such information is important because it helps us identify which patients should receive more aggressive treatment."
Some medical centers use MRI to identify sites of reduced blood flow in the heart, which can cause chest pain, and to measure how much blood is ejected by the left ventricle – the heart's main pumping chamber.
Hundley and his colleagues examined 279 men and women referred for MRI stress testing after their ultrasound screenings for heart disease were inconclusive. In an MRI stress test, drugs are used to stress the heart, then researchers study the reaction. Hundley notes the study yielded several important findings:
· Regardless of other risk factors, MRI can predict fatal and nonfatal heart attacks in patients whose left ventricle pumps out less than two-thirds of the blood a normal heart ejects;
· Someone whose damaged heart wall moves better at rest than when stressed also has an elevated risk; and
· The location in the heart of reduced blood flow or muscle damage apparently influences risk. Reduced blood flow in the apex of the left ventricle indicates a higher risk.
"These findings have interesting implications," Hundley says. "Patients with isolated disease near the base and the middle of the ventricle often are referred for procedures to restore blood flow. This study suggests that in doing so, you might alleviate chest pain but not prevent a cardiac death."
Co-authors are Timothy M. Morgan, Ph.D.; Christina M. Neagle, L.P.N.; Craig A. Hamilton, Ph.D.; Pairoj Rerkpattanapipat, M.D.; and Kerry M. Link, M.D. The study was partly funded by the National
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