Abstract 17124: Utility of Magnetocardiography for Evaluating Arrhythmogenic Right Ventricular Cardiomyopathy
Signal averaged ECG (SAECG) is an important tool for noninvasively detecting arrhythmogenic substrates in arrhythmogenic right ventricular cardiomyopathy (ARVC), however, its value is seriously limited in patients with wide QRS due to complete right bundle branch block (CRBBB). It also does not provide the spatial information to locate arrhythmogenic substrates. We hypothesized that magnetocardiography (MCG) with high spatial resolution is useful for evaluating ARVC patients even presenting CRBBB.
Methods: We recorded 64-Ch MCGs (1kHz, >30sec) and standard SAECG in 25 consecutive ARCV patients (19 males, 49 ± 16 y.o.) with ventricular tachycardia who underwent invasive electrophysiological studies (EPS). 64 MCG QRS complexes were used to obtain 2-D mapping, by which we determined the presence and site of abnormally delayed ventricular conduction. The latest activation site on MCG was compared with the EPS-determined location representing double or fractionated potentials (DP/FP). Patients with isolated CRBBB without structural disease (n=15) served for comparison.
Results: On SAECG, late potentials (LP) was found in 14 of 15 patients with QRS<110ms, but undetermined in 10 with QRS ≥110ms. On MCG, in all of 25, we could observe heterogeneous RV currents slowly propagating at specific sites of RV region, which could be differentiated form isolated CRBBB pattern (slow but homogeneous conduction). The latest activation site on MCG were coincident with the DP/FP site in 23/25 (92%, RVOT in 3, inferior in 12, septum in 2, and anterior to lateral in 6), but not in only 2 (inferior by EPS but RVOT on MCG).
Conclusions: Multi-channel MCG has a potential to detect and locate arrhythmogenic substrates in ARVC patients, even presenting CRBBB. A spatially close distance between the sensors (placed as close as possible to the chest wall) and right ventricle would contribute the ability of MCG to sensitively detect subtle electrical activities in ARVC.
- © 2012 by American Heart Association, Inc.