Epsilon Wave Definition

  • Small positive deflection (“blip” or “wiggle”) buried in the end of the QRS complex
  • Best seen in ST segment of V1 and V2, they are usually present in leads V1 through V4
  • Caused by post-excitation of myocytes in the right ventricle
  • Characteristic finding in patients with arrhythmogenic right ventricular dysplasia (ARVD)
Epsilon Waves
Epsilon wave in V1 due to RV conduction delay

Epsilon waves are the most specific and characteristic finding in arrhythmogenic right ventricular dysplasia (ARVD). In ARVD, myocytes are replaced by fat, producing islands of viable myocytes in a sea of fat. This causes a delay in excitation of some of the myocytes of the right ventricle, producing a small “blip” seen during the ST segment of the ECG.

Epsilon waves have also been described in patients with:

  • Posterior myocardial infarction
  • Right ventricular infarction
  • Infiltrative disease
  • Sarcoidosis

History of the Epsilon Wave

The Epsilon waves in arrhythmogenic right ventricular dysplasia were first defined and described in 1977 by Guy Fontaine (1936-2018). The waves may be seen more readily using Fontaine leads.

The term “epsilon” was nice, because it occurs in the Greek alphabet after delta; thus, delta represents the pre-excitation and epsilon the post-excitation phenomenon. In addition, epsilon is also used in mathematics to express a very small phenomenon…

Fontaine 1997

Fontaine bipolar precordial leads (F-ECG) can be used to increase the sensitivity of epsilon wave detection. Leads are placed as shown:

  • Right Arm (RA) over the manubrium;
  • Left Arm (LA) over the xiphoid process;
  • and Left Leg (LL) in the standard V4 position (5th ICS MCL).

Instead of regular leads I, II, and III there are now three bipolar chest leads that are termed FI, FII, and FIII which record the potentials developed in the right ventricle, from the infundibulum to the diaphragm.

The vertical bipolar lead FI, (similar to aVF) magnifies the atrial potentials and can be used to record:

  • epsilon waves;
  • search for AV dissociation in ventricular tachycardia;
  • and to study abnormal atrial rhythms when the P waves are too small on regular leads.
Fontaine bipolar precordial lead electrocardiography (F-ECG)
Fontaine bipolar precordial leads (F-ECG)

ECG Examples of Epsilon Waves

Arrhythmogenic Right Ventricular Dysplasia (ARVD)

The ECG changes in Arrhythmogenic Right Ventricular Dysplasia include:

  • Epsilon wave (most specific finding, seen in 50% of patients)
  • T wave inversions in V1-3 (85% of patients)
  • Prolonged S-wave upstroke of 55ms in V1-3 (95% of patients)
  • Localised QRS widening of 110ms in V1-3
  • Paroxysmal episodes of ventricular tachycardia with a LBBB morphology (RVOT tachycardia)

ECG Examples
Example 1
  • 12-lead ECG is a typical example of ARVD.

Prolonged S-wave upstroke in ARVD
Prolonged S-wave upstroke in ARVD

Example 2
Arrhythmogenic Right Ventricular Dysplasia (ARVD) 002
VT with LBBB morphology due to ARVD

  • Corrado D, Biffi A, Basso C, Pelliccia A, Thiene G. Twelve-lead ECG in the athlete: physiological versus pathological abnormalities. Br J Sports Med 2009; 43: 669-676. [PMID: 19734501]
  • Perez Diez D, Brugada J. Diagnosis and Management of Arrhythmogenic Right Ventricular Dysplasia: An article from the E-Journal of the ESC Council for Cardiology Practice, European Society of Cardiology 2008.
  • Fontaine G et al. Stimulation studies and epicardial mapping in ventricular tachycardia: study of mechanisms and selection for surgery. In: Kulbertus HE, ed. Re-entrant Arrhythmias: Mechanisms and Treatment. 1977: 334 –350.
  • B. Gottschalk et al. The use of Fontaine leads in the diagnosis of arrhythmogenic right ventricular dysplasia. Ann Noninvasive Electrocardiol, 2014; 19(3): 279-284

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Emergency physician MA (Oxon) MBChB (Edin) FACEM FFSEM with a passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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