Integral Value of JT Interval in Magnetocardiography is Sensitive to Coronary Stenosis and Improves Soon After Coronary Revascularization

Abstract

Background Magnetocardiography (MCG) is sensitive to minute cardiac electric abnormalities, but its clinical utility in diagnosing ischemic heart disease (IHD) has not been established. The present study examined the usefulness of an integral MCG value of ventricular repolarization in patients with IHD. Methods and Results MCG was performed at rest in 14 patients with coronary stenosis >75% confirmed by coronary angiography (IHD group) using a 64-channel system, and then the sum of the 64-channel integral values of the QRS or JT intervals (QRSi and JTi, respectively) was calculated. The JTi/QRSi value indicated the total power of currents in JT compared with those in QRS. These measurements were repeated within 2 weeks after coronary revascularization. The Control group comprised 30 healthy volunteers. The baseline value of JTi/QRSi was significantly smaller in the IHD than in the Control group, but after revascularization it increased and did not significantly differ from the Control group. No significant difference in ST deviation was identified by electrocardiography (ECG) before and after coronary revascularization. Analysis of the Control group revealed that JTi/QRSi was not affected by age. Conclusions The JTi/QRSi of the MCG is more sensitive to coronary stenosis than ECG, and this parameter improves soon after coronary revascularization. (Circ J 2007; 71: 1586 -1592

Magnetocardiography in Early Detection of Electromagnetic Abnormality in Ischemic Heart Disease

“…Figure 19 Comparison of JTi/QRSi among 3 control subgroups. 44) Age-dependent differences in JTi/QRSi were undetectable.…”

“…Reported methods on the MCG diagnosis of IHD are summarized as follows: 1. magnetic measurement of ST and TQ segment shift, Figure 17 Comparison of JTi/QRSi between control and IHD groups before and after coronary revascularization. 44) QRSi, JTi are the total sums of the QRS integral and JT integral values of 64 channels, respectively. JTi/QRSi is significantly smaller in patients with coronary stenosis compared with healthy controls, and it improved after coronary revascularization and no longer significantly differed from the control value.…”

Validation of magnetocardiography versus fractional flow reserve for detection of coronary artery disease

“…In various clinical studies superior sensitivity of MCG for ischemic myocardium at rest, as well as under stress has already been shown [14,15,30,31,50]. Recently, MCG has been recognized for its outstanding ability to detect patients with coronary artery disease [11,13,36,37]. In a 3-year follow-up we found the highest mortality risk for emergency patients with an abnormal MCG on admission [39].…”

Magnetocardiography in Early Detection of Electromagnetic Abnormality in Ischemic Heart Disease

“…Figure 18 ST deviation after coronary revascularization in IHD group. 44) No significant changes in ST deviation were observed after coronary revascularization despite the improvement of MCG findings.…”

“…To confirm these observations, we calculated the total sum of the QRS integral and JT integral values of 64 channels (QRSi, JTi), and compared them between the patients with IHD and normal controls. 44) The QRSi and JTi represent the total current intensity of the whole heart during each time x Figure 16 Iso-integral maps during QRS and JT in patients with IHD. 34) The highest integral values are listed in the maps.…”