The study of QT dispersion variability in patients with coronary artery disease using magnetocardiography

Objective: The aim of the present study was the temporal and spatial analysis of the QT interval in healthy subjects and in patients suspected coronary artery disease（CAD）using magnetocardiography（MCG）to measurement variability of repolarisation. Methods: Standard 12-lead ECG and 61 channel MCG were performed in 35 healthy subjects;75 patients suspected CAD,35 patients without CAD and 34 patients with CAD and 10 patients with myocardial infarction（MI）.For MCG,spatial dispersion was examined by the QT interval value for each channel relative to its position and quantified on the basis of Smoothness Indexes（SI）. Results: There was an overall tendency of MCG-QTd and SI values to be higher for the subjects with CAD and MI,MCG-QTd values was better than ECG-QTd,it able to discriminate relevant groups. SI performed better than MCG-QTd;it could significantly discriminate CAD and MI groups from healthy subjects group. Comparison the healthy subjects group to CAD group,we obtain sensitivity of 78.2% and specificity of 81.6% in CAD diagnostically relevant values with SI. Conclusion: MCG-QTd and SI values were higher than ECG-QTd in CAD patients.It suggest that increasing the number of registration sites and examining the spatial inter-lead variability,it may aid in the initial identification of CAD patients from healthy subjects group.