Epsilon Waves

The epsilon wave consists of high-frequency notches located on the ST segment immediately after the QRS complex, usually recorded in the right precordial leads on the standard ECG (Fig. 13.3). This ECG wave was first described in patients with ARVC/D [2, 20]. It is believed that epsilon waves represent delayed activation of affected areas of right ventricle. Late potentials in the signal average ECG (SAECG) are another manifestation of the same phenomenon. It is recommended that the ECG should be recorded at double speed (50 mm/s) and double amplitude (20 mm/mv) to increase the sensitivity to detect epsilon waves. Improvement in detecting epsilon waves can also be obtained by using the limb leads placed on the chest with the left arm lead over the xyphoid process, the right arm lead on the manubrium sternum, and the left leg lead over a rib at the V4 or V5 position [24]. Further

Fig.13.3 • Epsilon wave in V1 and V2 in the presence of right bundle branch block

enhancement can be obtained by resetting the filter of the ECG machine from the usual 150 Hz to 40 Hz.

Wichter et al. [17] found epsilon waves in 22.5% of 151 ARVC/D patients and late potentials in 41% of the 151 patients. Turrini et al. [18] reported epsilon waves in 25%-35% of patients with different arrhythmogenic potential. These data suggest that the epsilon wave is not predictive of arrhythmic events. In a series of 265 patients, Peters et al. [21] recorded precordial epsilon waves using the standard ECG setting in 23% and using highly amplified and modified recording technique in 75% of the patients.

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