Abstract 2768: Relation Between Signal-Averaged Electrocardiogram and Electroanatomic Mapping in Arrhythmogenic Right Ventricular Cardiomyopathy
Background. Areas with fibrofatty replacement in the RV wall form the basis for reentry in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). Signal-averaged electrocardiogram (SAECG) abnormalities are frequent and may reflect the presence of arrhythmogenic areas in these patients. Recent data show that also low-voltage areas (LVA) on 3-dimensional electroanatomic voltage mapping (EVM) may identify diseased areas in the RV wall. We tested the association between SAECG and low-voltage regions on EVM in patients with ARVC/D.
Methods. Twenty consecutive patients (age 40±16 years, 11 men) who fulfilled the criteria of the Task Force of the European Society of Cardiology and International Society and Federation of Cardiology (ESC/ISFC) for ARVC/D diagnosis and had histological evidence of fibrofatty replacement at EVM-guided endomyocardial biopsy underwent right ventricular EVM and SAECG with 40 Hz filtering. A filtered averaged QRS (fQRS) was obtained and analyzed for fQRS duration, low amplitude signal duration below 40 μV (LAS40) and root mean square voltage in last 40 ms of the QRS (RMS40). LVA at EVM were defined as mean electrogram voltage <1.5 mV in ≥1 RV areas.
Results. Multiple bipolar electrograms (155±36) during sinus rhythm were sampled in the RV outflow tract (RVOT), in the RV septal wall (RVSW), in the RV free wall (RVFW), in the RV posterior wall (RVPW) and in the RV apex (RVA). LVA were present in 11 patients (55%) and were localized in the RVOT in 6 patients (54%), in the RVPW in 7 (63%), in the RVFW in 2 (18%) and in the RVA in 1 patient (9%). Patients with ≥1 LVA on EVM showed longer fQRS than patients with normal EVM (114.5±20 vs. 94.4±13 ms, respectively, P=0.01) and longer LAS40 (51.7±24 vs. 35.2±9 ms, respectively, P=0.05). A significant correlation was found between all SAECG parameters and mean bipolar electrogram voltage amplitude in the RVOT (r=−0.65, P=0.002 for fQRS; r=−0.62, P=0.004 for LAS40; r=0.59, P=0.006 for RMS40), but not between SAECG parameters and electrogram voltages in other RV areas. An fQRS>114 ms was predictive of LVA in the RVOT with a sensitivity of 84% and a specificity of 93%.
Conclusion. In patients with ARVC/D, abnormal SAECG parameters reflect the presence of low voltage areas in the RVOT.