Correlation between epsilon wave and late potentials in arrythmogenic right ventricular cardiomyopathy. Do late potentials define the epsilon wave?
Authors: Skrzypczynska-Banasik U , Biernacka E K , Fronczak-Jakubczyk A , Wozniak O , Borowiec K , Hoffman P 
Published: November 2023

Abstract

Introduction
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder characterised by progressive fibrosis predominantly of the right ventricular (RV) myocardium resulting in life-threatening arrhythmias and heart failure. The diagnosis is challenging due to a wide spectrum of clinical symptoms. The important role of ECG was covered in the current diagnostic criteria. The role of epsilon wave (EW) is still under discussion.

Aim
The aim of the study was to correlate the presence of EW with late ventricular potentials (LPs) in ARVC patients (pts). The correlation between RV dilatation /dysfunction and LPs/EW was also analysed.

Methods
The ARVC group consisted of 81 pts (53 men, aged 20-78 years) fulfilling 2010 International Task Force Criteria. 12-lead ECG, LPs, Holter, ECHO were performed in all pts. The presence of EW, defined as low-amplitude deflection observed between the end of the QRS complex and the onset of the T wave was analysed in ECG by 3 investigators. LPs were defined as low-amplitude, high-frequency waveforms at the end of the QRS complex on signal-averaged ECG (SAECG). SAECG was considered positive for LPs when at least two of the three following criteria were met: filtered QRS duration (fQRS) &gt;114 ms, root-mean-square voltage in the terminal 40 ms (RMS 40) &lt;20 uV, or low amplitude (&lt;40 µV) signal (LAS 40) duration &gt;38 ms. The results were compared with a reference group consisting of 53 pts with RV damage in the course of atrial septum defect (ASD) (29 pts, 8 men, aged 22-80 years) or Ebstein Anomaly (EA) (24 pts, 11 men, aged 23-55 years).

Results
In the ARVC group, a significant relationship was observed between the occurrence of EW and the presence of LPs. EW was more common in LP+ than in LP- patients (48.1% vs 6.9%, p&lt;0001; OR 12.5). In ARVC a relationship was also found between the presence of LPs and increased RV inflow tract (RVIT) and RV outflow tract (RVOT) dimensions, as well as a reduced RV S' wave value. RVOT &gt;36 mm, RVIT &gt;41 mm and RV S’ &lt;9 cm/s were observed significantly more often in the LPs+ than in LPs- group (OR: 8.3, 6.4 and 3.6, respectively). In the ARVC group, any of fQRS &gt;114 ms, LAS &gt;38 ms, and RMS &lt;20 uV were significantly more frequent in EW+ pts. In multivariate analysis, the only independent factor of the EW was fQRS (OR: 1.043 [1.020-1.067], p&lt;0.001; AUC: 0.852). In the LPs- subgroup, RVOT &gt;36 mm was more frequent in ASD/EA than in ARVC (70.4% vs 25%, p=0.002). Similarly, in the LPs- subgroup, RVIT &gt;41 mm was encountered more frequently in ASD/EA than in ARVC (85.2% vs 48.3%, p=0.004).

Conclusions
In ARVC, there is an association between EW and LPs, with both probably resulting from the same process of fibrofatty substitution of the RV myocardium. Although RV dilatation is common in ASD and EA, it does not correlate with LPs, possibly due to a lower degree of fibrosis in ASD/EA compared to ARVC.