MRI spots silent heart attacks
Test outperforms standard EKG in detecting unrecognized cardiac damage
By Nathan Seppa
Many people have had a heart attack and don’t know it. A study of older people in Iceland finds that nearly twice as many had experienced a silent heart attack as had suffered one with all the medical bells and whistles. MRI scans revealed the hidden heart attacks better than standard testing by electrocardiography, or EKG, scientists report in the Sept. 5 Journal of the American Medical Association.
It’s helpful to know who has had a heart attack because for the long term such people are treated more aggressively with medication, says study coauthor Andrew Arai, a cardiologist at the National Heart, Lung, and Blood Institute in Bethesda, Md.
Arai and his U.S. colleagues teamed with Icelandic researchers to test 670 people who were randomly selected from Iceland’s population and 266 others chosen because they had diabetes. The overall median age of the volunteers was 76. Medical records showed that 91 had experienced a previous heart attack. But testing with MRI revealed that 157 others, including 72 who had diabetes, had clear signs of cardiac tissue that was damaged at some point in a silent heart attack. EKG spotted 46 such cases, including 15 patients with diabetes. Some people, but not all, were detected by both diagnostic tests.
“The data are pretty unequivocal,” Arai says. “MRI is much more sensitive.” Those with undiagnosed heart attacks were substantially less likely to be getting drugs such as aspirin to limit blood clotting or statins to lower LDL cholesterol than were people who had a documented history of a heart attack.