Usefulness of Magnetocardiogram to Detect Unstable Angina Pectoris and Non-ST Elevation Myocardial Infarction

Electrophysiologic information as well as anatomic information to detect coronary artery disease is important for accurate diagnosis. A diagnostic tool that can detect patients with unstable angina pectoris (UAP) or non–ST elevation myocardial infarction (NSTEMI) with severe stenosis would be beneficial for patients and clinicians. Magnetocardiography has been recognized as a noncontact, noninvasive, fast tool to detect ischemic coronary artery disease and provide direct electrophysiologic information from the heart. In this study, 10 magnetocardiographic (MCG) parameters from 4 groups, including 185 young controls, 19 age-matched controls (AMCs), 110 patients with UAP, and 83 patients with NSTEMIs, were analyzed. A 64-channel MCG system in a magnetically shielded room was used. All 10 parameters showed significant differences (p <0.001) between controls and patients with NSTEMIs, and 6 parameters showed significant differences (p <0.01) between AMCs and patients with UAP. MCG parameters significantly increased when ischemic heart conditions worsened. Of the 10 parameters, the magnetic field map was among the easiest ways to detect the severity of coronary artery disease. Abnormal magnetic field maps were observed frequently with worsening ischemic coronary artery disease (70% of patients with UAP and 92.5% of those with NSTEMIs had abnormal maps). The combination of the binary boundaries of the 10 parameters had 96.4% sensitivity and 85% specificity to detect NSTEMI. In conclusion, the MCG parameters and magnetic field maps may detect UAP and NSTEMI easily when they are considered together.