Epsilon Wave Definition
The epsilon wave is a small positive deflection (‘blip’ or ‘wiggle’) buried in the end of the QRS complex. Epsilon waves are caused by postexcitation of the myocytes in the right ventricle.
Epsilon waves are the most characteristic finding in arrhythmogenic right ventricular dysplasia (ARVD/C). Here myocytes are replaced with 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 and causes the little wiggles seen during the ST segment of the ECG.
Epsilon waves have also been described in patients with posterior myocardial infarction; right ventricular infarction; infiltration disease, and sarcoidosis.
Epsilon waves are best seen in the ST segments of leads V1 and V2, and most commonly seen in leads V1 through V4.
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.
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 30% 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
- 12-lead ECG is a typical example of ARVD.
- Arrhythmogenic right ventricular dysplasia
- Right ventricular outflow tract VT
- ECG Exigency 008 — Sudden Syncope on the Soccer Field
- 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
ECG Library Basics
- Wiesbauer F, Kühn P. ECG Yellow Belt online course: Become an ECG expert. Medmastery
- Wiesbauer F, Kühn P. ECG Blue Belt online course: Learn to diagnose any rhythm problem. Medmastery
- Rawshani A. Clinical ECG Interpretation ECG Waves
- Smith SW. Dr Smith’s ECG blog.
- Mattu A, Tabas JA, Brady WJ. Electrocardiography in Emergency, Acute, and Critical Care. 2e, 2019
- Brady WJ, Lipinski MJ et al. Electrocardiogram in Clinical Medicine. 1e, 2020
- Straus DG, Schocken DD. Marriott’s Practical Electrocardiography 13e, 2021
- Hampton J. The ECG Made Practical 7e, 2019
- Grauer K. ECG Pocket Brain (Expanded) 6e, 2014
- Brady WJ, Truwit JD. Critical Decisions in Emergency and Acute Care Electrocardiography 1e, 2009
- Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric 6e, 2008
- Mattu A, Brady W. ECG’s for the Emergency Physician Part I 1e, 2003 and Part II
- Chan TC. ECG in Emergency Medicine and Acute Care 1e, 2004
LITFL Further Reading
- ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation
- ECG A to Z by diagnosis – ECG interpretation in clinical context
- ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases
- 100 ECG Quiz – Self-assessment tool for examination practice
- ECG Reference SITES and BOOKS – the best of the rest