Search

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)

Background Carotid arterial ultrasound examination may be helpful for screening populations at high risk for acute coronary syndrome (ACS), so the present study was designed to identify the carotid arterial characteristics of patients with ACS. Methods and Results Carotid ultrasound examinations were performed in 172 patients with ACS, 166 patients with stable coronary artery disease (CAD), and 96 control subjects. Common carotid arterial structures were assessed by the intima - media thickness (IMT), interadventitial diameter (IAD), lumen diameter (LD), the IMT to LD ratio (IMT/LD), and the plaque burden based on the plaque score. Plaque morphology was assessed by the echogenecity based on the gray-scale median (GSM). IMT, IAD, IMT/LD, and plaque score did not differ between the ACS and stable CAD groups. The GSM in the ACS group was lower (47.5±25.3, p

Background In patients with chronic heart failure, an inadequate increase in muscle blood flow resulting from impaired vasodilation plays a key role in their exercise intolerance. However, no non-invasive methods to assess muscle vasodilation during dynamic exercise were available. We investigated whether the changes in tissue hemoglobin and myoglobin content (total-Hb + Mb) determined by non-invasive measurement using near-infrared spectroscopy (NIRS) reflect vessel conductance of working muscle during exercise. Methods and Results Sixteen patients (10 patients with normal cardiac systolic function, 6 with cardiac dysfunction) performed incremental bicycle exercise testing. Total-Hb + Mb from the right vastus lateralis muscle was monitored using NIRS. Leg blood flow (LBF) in the right femoral vein was measured using a thermodilution technique every 30-60 s. Leg vessel conductance was calculated as LBF/mean arterial pressure at each time of the measurement. In all cases except 1, the levels of total-Hb + Mb showed significant correlation with the leg vessel conductance (r=0.792 to 0.980). Intra-subject reproducibility of the NIRS measurement was also confirmed in 6 patients. Conclusions Total-Hb + Mb from NIRS reflected muscle vasodilation during sub-maximal dynamic exercise in patients with and without cardiac dysfunction, indicating that NIRS provides a valuable method to assess the working muscle vasodilation. (Circ J 2005; 69: 802 - 814)