QT_cheterogeneity in rest magnetocardiography is sensitive to detect coronary artery disease: In comparison with stress myocardial perfusion imaging

Background: Stress nuclear myocardial perfusion imaging (MPI) is an established method for diagnosis and prognosis of coronary artery disease (CAD). However, radiation exposure limits its clinical application. Magnetocardiography (MCG) has been proposed as a non-contact, rapid and non-radiation technique with high reproducibility. The aim of the study was to evaluate the diagnostic efficacy of rest MCG in CAD comparing to stress MPI.

Methods: We prospectively enrolled 55 patients with suspected CAD (64 ± 10 years) who were scheduled for coronary angiography (CA).MCG, stress ²⁰¹Tl MPI and CAwere performed within 3 months. The spatial distribution maps of QT_cinterval (21 × 21 in resolution) were derived from a 64-channel MCG system (KRISS, Korea). T-wave propagation mapping, repolarization heterogeneity index with QT_cdispersion and smoothness index of QT_c(SI-QT_c) were analyzed, and the diagnostic criteria for CAD were developed based on the receiver operating characteristic (ROC) curve analysis.

Results: Patients with significant CAD (≥ 70% luminal stenosis, n = 36) had higher QT_cdispersion and SI-QT_cthan controls (both p < 0.05). The diagnostic sensitivity and specificity were 0.8330, 0.6842 for QT_cdispersion ≥ 79 ms; 0.7778, 0.6842 for SI-QT_c≥ 9.1ms; and 0.8611, 0.6842 for combination. There was no difference of area under ROC curve by using criteria of QT_cdispersion ≥ 79 ms, SI-QT_c≥ 9.1 ms or combination (0.7588, 0.7310, 0.7727, p = NS), and non-inferior to stress MPI (p = NS).

Conclusions: The QT_cheterogeneity parameters of rest MCG yield a good sensitivity and acceptable specificity for detection of CAD, and may provide an alternative to stress MPI without stress and radiation.