Value Of Magnetocardiography In The Diagnosis Of Coronary Heart Disease And Left Ventricular Hypertrophy

Objective:To investigate the diagnostic value of Magnetocardiography (MCG) in coronary heart disease and hypertensive left ventricular hypertrophyMethods:First,195cases of patients performed with myocardialperfusion imaging (MPI) examinations, simultaneously MCG measurements, were divided into MPI-positive myocardial ischemia group and MPI-negative control group, the value of MCG in the diagnosis of myocardial ischemia was evaluated by comparing with two groups.Then104patients with coronary angiography (CAG) checks of195patients were classified as CAG-positive coronary heart disease group and CAG-negative non-coronary heart disease group, observed diagnostic value of MCG and MPI in coronary heart disease. Second,205patients with echocardiography (UCG),CAG and MCQwere divided into left ventricular hypertrophy group and control group by UCG. Control group consisted of112cases (wall thickness<12mm), with negative CAG.93patients with left ventricular hypertrophy (wall thickness=12mm) were divided into two groups according to CAG, including CAG-negative simple hypertrophy group (34cases) and CAG-positive hypertrophy group (59cases). Compared the differences between groups, the diagnostic criteria of left ventricular hypertrophy in QRS wave maximum magnetic flux (R1), QRS wave minimum magnetic flux (R2), and amplitude of QRS wave that was obtained by maximum magnetic flux of QRS wave subducing the minimum flux magnetic flux of QRS wave (R1-R2) were determined,and the value of MCG in the diagnosis of left ventricular hypertrophy was observed.Finally, according to the history of hypertension, control group was divided into two groups including simple control group of63patients and control group with hypertension of49patients,to get the changes of MCG with hypertension.Results:(1) When we set MPI as criteria for myocardial ischemia,the diagnostic sensitivity of Pre-Angle, Pre-Trajectory, Pre-Angular Deviation, Post-Angle Post-Trajectory, Post-Angular Deviation, Pre-Post Angle Change was54.35%,,32.61%,39.13%,45.65%,43.48%,58.70%,24.91%respectively, the specificity was 79.00%,68.91%,62.91%,88.24%,70.59%,68.91%,89.92%respectively. Three or more paramenters were positive, the sensitivity for diagnosis of coronary heart disease was52.17%and specificity was74.79%.(2)If setting CAG as the standard of coronary heart disease, we would get the seven parameters of MCG respectively with sensitivity of50.00%,36.36%and62.50%,50.00%,53.12%,71.88%,25.00%, specificity of81.94%,68.06%and62.50%,83.33%,62.50%,62.50%,87.50%; MCG7parameters of any two or more positive, with a sensitivity of81.25%, specificity of59.72%, more than any three positive, with a sensitivity of65.63%, specificity of69.44%; MPI in diagnosis of coronary heart disease with a sensitivity of75.00%, specificity of79.20%.(3) By simple hypertrophy group compared with the control group we determined the R1, R2and R1-R2of the diagnostic criteria for left ventricular hypertrophy as R1<18.5pT,R2>-10pT and R1-R2<28pT.The sensitivity of them for left ventricular hypertrophy was58.82%,55.88%,55.88%, and specificity was68.75%,80.36%,71.43%.MCG7parameters in Pre-peak repolarization Angle sensitivity,specificity,accuracy,positive likelihood ratio,and Youdon indices were61.76%,85.71%,80.14%,4.32,0.47,Post-peak repolarization Angle,respectively58.82%,90.17%,82.88%,5.99,0.49; MCG7parameters three or more positive, sensitivity was64.71%and specificity was69.64%; four or more parameters positive, sensitivity and specificity were55.88%and77.68%respectively.MCG parameters between simple hypertrophy group and CAG-positive hypertrophy group had no statistic differences, combined the two groups as left ventricular hypertrophy group, when compared with left ventricular hypertrophy group and the control group,sensitivity of R1, R2, R1-R2for diagnosis of left ventricular hypertrophy decreased slightly than previous and seven parameters of sensitivity, specificity had no significant difference.Pre-peak repolarization Angular Deviation, T wave maximum magnetic flux (T1), T wave minimum magnetic flux (T2), and amplitude of T wave that was obtained by maximum magnetic flux of T wave subducing the minimum flux magnetic flux of T wave (T1-T2) between simple control group and control group with hypertension had no statistic difference.Conclusions:1. In the diagnosis of myocardial ischemia,MCG and MPI had good value in clinical application.2. MCG in the diagnosis of hypertensive left ventricular hypertrophy has a good prospect in clinical application.3.MCG can detect early changes of cardiac repolarization in hypertension.