Abstract 12613: Extremely Delayed Conduction Detectable on Magnetocardiography Predicts Future Lethal Arrhythmic Events in Arrhythmogenic Right Ventricular Cardiomyopathy
Backgrounds: Because of its clinically heterogeneous nature, identifying individuals at high risk for lethal ventricular tachycardia (VT) remains challenging in arrhythmogenic right ventricular cardiomyopathy (ARVC). Indication for implantable cardioverter defibrillator (ICD) implantation has not been established, especially in those without spontaneous VT. Magnetocardiography (MCG) with high spatio-temporal resolution may be useful for detecting extremely delayed conduction (ExDC) directly linked to the occurrence of VT, possibly predicting future arrhythmic events.
Methods: Multi-channel (64Ch, 1kHz) MCG analysis yielding 2-D current arrow map was performed in 40 patients with ARVC diagnosed according to the "Task Force" criteria. Sustained VT (sVT) was previously documented in 32, but not in 8. We defined ExDC to be present when apparently discrete activations re-emerged in RV area after the decay of main RV activation (an interval from peak currents >30ms and %magnitude >5% of Max).
Results: ExDC was recognized in 18 (45%, Group-A), but not in 22 (Group-B). Age, QRS duration, epsilon-wave, late potentials on SAECG, RVEF, LVEF and other parameters were comparable between the groups. During the follow-up of 1273 ± 777 days, lethal arrhythmic events (sudden cardiac death in 1, sVT in 3 and appropriate ICD discharge in 4) were more frequently found in Group-A (39%, 7/18) than in Group-B (5%, 1/22, p=0.009). Multivariate analysis revealed ExDC as the only independent predictor (HR=9.0; 95% CI:1.6-170.2; p=0.011).
Conclusions: Magnetocardiographic analysis is useful to delineate extremely delayed conduction in ARVC, possibly directly linked to ventricular arrhythmias. This finding may help identify the subset at high risk for future arrhythmic events. A spatially close distance between the sensors (placed as close as possible to the chest) and right ventricle might contribute to sensitively detect subtle abnormal electrical activities in ARVC.
- © 2013 by American Heart Association, Inc.