Diagnostic outcomes of magnetocardiography in patients with coronary artery disease

Abstract

Objective: To evaluate the diagnostic outcomes of magnetocardiography (MCG) on the patients with coronary artery disease and compared the outcomes between MCG, ECG and Echocardiography.

Methods: MCG measurements were performed on 101 patients with coronary artery disease and 116 healthy volunteers with a seven-channel magnetocardiographic system (MCG7, SQUID AG, Germany) installed in an unshielded room. CAD was diagnosed when stenosis ≥ 70% in ≥ 1 vessel. Three quantitative indicators were analyzed, R-max/T-max ratio, R value and á average angle.

Results: R-max/T-max ratio of CAD group (6.30 ± 4.07) was much higher than that of healthy group (3.73 ± 1.41) (P < 0.001), R value of CAD group (69.16 ± 27.87)% was significantly higher than that of healthy group (34.96 ± 19.09)% (P < 0.001), á average angle of CAD group (221.46° ± 64.53°) was higher than that of healthy group (24.32° ± 20.70°) (P < 0.01). In 75 of 101 CAD patients (74.26%), MCG had abnormal mapping patterns. The resting ECG examination showed ischemic changes, such as abnormal Q waves and ST-T change in 49 patients (48.51%). Echocardiography revealed abnormal left ventricular wall motion and asynergy in 46 patients (45.54%). Thus, the diagnostic outcomes of MCG for the patients with CAD were much significant than those of ECG and echocardiography (P < 0.001).

Conclusions: Our result showed that resting MCG under condition of an advanced data analysis has higher diagnostic outcomes and is superior to ECG or echocardiography for patients with CAD. MCG can detect ST-segment displacement caused by ischemic myocardium, thus helpful in diagnosing coronary artery disease early.

Keywords: Magnetocardiography (MCG); coronary artery disease (CAD); current density distribution map (CDDM); echocardiography; electrocardiogram (ECG); magnetic field map (MFM).

Figures

Figure 2

Current density distribution maps of healthy person (left) and CAD patient with triple-vessel disease (Right). Class 0: dopole structure, two vortexes, orientation: 0°~8° (left); Class 4: non-dipole structure, more than two vortexes, non-clear orientation: -20°~110° (Right).

Figure 1

Current density distribution maps of healthy person (left) and transient vectorcardiogram (middle), the direction of the maximal vector is 35 (At the moment of T-wave apex). Note: Green area: normal; Yellow area: critical; Red area abnormal (transient Vectorcardiogram).

Figure 3

Magnetic field maps of healthy person (left) and CAD patient with triple-vessel disease (right) (At the moment of T-wave apex).