Managing chest pain is a challenge for every ED, fraught with risks of missed diagnosis, adverse outcomes, and potential lawsuits. As an ED manager, you should take note of a new study reporting that magnetic resonance imaging (MRI) technology can detect heart attacks faster than other methods in ED patients with chest pain.1 The study, conducted by the Bethesda, MD-based National Institutes of Health (NIH), says that more patients with a heart attack or major blockage would be able to receive treatment to reduce permanent damage if they were given an MRI.
The researchers compared the MRI results with three standard diagnostic tests: an electrocardiogram (ECG), a blood enzyme test, and the Thrombolysis in Myocardial Infarction risk score, which assesses the risk of complications or death in patients with chest pain. MRI detected all of the patients’ heart attacks, including three in patients who had normal ECGs. In addition, MRI detected more patients with unstable angina than the other tests.
The study shows that better strategies are needed for chest pain patients when the initial ECG and troponin level do not make the diagnosis, says Andrew Arai, MD, an NIH investigator and one of the study’s authors. "Detecting the patient with a myocardial infarction despite normal ECG is relatively easy by MRI," he says.
Patients with a minimally abnormal ECG but MI in process, and patients with unstable angina, may be more accurately diagnosed with an MRI scan, Arai says. With MRI, you can detect patients with unstable angina, he adds. "Cardiac enzymes theoretically should always miss the patient with no infarction," Arai says. "The ECG is not sensitive or specific enough to accurately diagnose these patients."
Use of MRI could fundamentally change the approach to patients who are not immediately diagnosed by simpler tests on presentation, says Arai. "ED managers and physicians need to help participate in developing reasonable new strategies for diagnosis of patients with chest pain," he says.
Currently, physicians rely heavily on the ECG, which may show nonspecific changes, so many patients end up being admitted to "rule out" MI. "Many of these patients do not need hospitalization. So an MRI might reduce some fraction of rule out MI’ hospitalizations," Arai says.
1. Kwong RY, Schussheim AE, Rekhraj S, et al. Detecting acute coronary syndrome in the emergency department with cardiac magnetic resonance imaging. Circulation 2003; 107: 531-537.
For more information on the study, contact:
• Andrew Arai, MD, Investigator, National Heart, Lung and Blood Institute, National Institutes of Health, Department of Health and Human Services, 10 Center Drive, Bethesda, MD 20892-1061. E-mail: AraiA@NHLBI.NIH.GOV.