Abstract 12922: Noninvasive Risk Stratification of Lethal Ventricular Arrhythmias using 64-channel Magnetocardiography in Patients with Dilated Cardiomyopathy
Background: Heterogeneity of ventricular repolarization is known to be one of the potent arrhythmic substrates in idiopathic dilated cardiomyopathy (DCM). However, non-invasive evaluations of the repolarization abnormality such as QT-dispersion (QT-D) for lethal ventricular arrhythmias (VT/VF) are still controversial. We hypothesized an integral value of repolarization in 64-channel magnetocardiography (MCG) could noninvasively stratify the risk of VT/VF in DCM patients.
Methods: : 64-channel MCG and 12-lead ECG were simultaneously recorded in 71 DCM patients (mean age: 51±20 years, 55 male, LVEF: 28±11%). We automatically analyzed QT-D of 12-ECG and 64-MCG, sum of the 64-MCG integral values of the QT-D interval compensated with that of the JT interval (QTDi/JTi), which indicate that total power of currents in the QT-D interval compared with those in JT interval. We evaluated these ECG or MCG parameters and subsequent VT/VF events.
Results: During follow-up of 2.5±1.5 years, 15 of 71 (21%) patients had VT/VF events. Although QT-D of 12-ECG, QRS duration, history of non-sustained VT were not associated with the arrhythmic events, larger QT-D of MCG (>55ms; p=0.02), QTDi/JTi (>0.1; p=0.009) were associated with arrhythmic events (figure A and B). Positive of both two MCG repolarization abnormalities indicated a higher incidence of VT/VF compared to others (figure C). Lower LVEF was also associated with arrhythmic events (p=0.01), however, multivariate logistic regression analysis revealed that positive of two MCG repolarization abnormalities were the only independent predictor for subsequent VT/VF events in DCM patients (Odds ratio= 16.0, 95%CI=2.6-314.2, p≤0.01).
Conclusion: 64-channel MCG could noninvasively demonstrate heterogeneity of ventricular repolarization, which may help stratify the risk of lethal ventricular arrhythmias in DCM patients.
- © 2013 by American Heart Association, Inc.