Fontaine bipolar precordial leads (F-ECG) are used to increase the sensitivity of epsilon wave detection, characteristic of arrhythmogenic right ventricular dysplasia (ARVD/C)

Epsilon waves are the most specific and characteristic finding in ARVD caused by post-excitation of myocytes in the right ventricle. They are seen as a small deflections (“blip” or “wiggle”) buried in the end, or immediately following the QRS complex.

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
epsilon-V1b-590x182 2
Epsilon wave

Epsilon waves can be detected by:

  1. S-ECG: Standard 12-lead electrocardiography (S-ECG)
  2. R-ECG; Right-sided precordial lead electrocardiography (R-ECG)
  3. F-ECG; Fontaine bipolar precordial lead electrocardiography (F-ECG)

On the standard 12-lead ECG (S-ECG) they are usually present in unipolar leads V1 through V4, and best seen in the ST segment of V1 and V2.

In 30% of cases, specific changes may be recorded, such as ventricular post-excitation waves. These are potentials of small amplitude that have been called the Epsilon waves. They occur after the QRS complex at the beginning of the ST segment and reflect on the surface ECG the presence of delayed activation of some right ventricular fibers. 

Fontaine 1999

Guy Hugues Fontaine (1936-2018) was a French cardiologist and electrophysiologist. He provided the name for ARVD; the epsilon wave; and the Fontaine lead placement to best amplify the waves on an ECG

Fontaine lead placement

Fontaine bipolar precordial leads (F-ECG) can be used to increase the sensitivity of epsilon wave detection in ARVD. For example, Peters et al detected epsilon waves in 23% of their study sample by S-ECG and in 75% by F-ECG.

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.

  • Right Arm (RA) electrode on the manubrium;
  • Left Arm (LA) electrode over the xiphoid process;
  • Left Leg (LL) electrode in the standard V4 position (5th ICS MCL).
  • Creating F-ECG with FI, FII, FIII leads

Note: Increasing calibration from 10 to 20mm/mV; and paper speed from 25 to 50mm/second can further amplify the atrial activity.

Fontaine lead placement FI F II F III
Fontaine lead placement
Fontaine lead placement FI F II F III with heart and vectors
Fontaine lead placement
Lead naming

Classically, the diagrams showing the Fontaine vector triangle demonstrate FII as LA to LL and with FII from RA to LL. However, we feel the diagram is more accurately represented as above, based on Fontaine’s original description:

  • Fontaine Lead I: RA (-) to LA (+)
  • Fontaine Lead II: RA (-) to LL (+)
  • Fontaine Lead III: LA (-) to LL (+)

[Epsilon] waves are better demonstrated by placement of a suction electrode connected to the right arm connection (negative) on the manubrium sternum and the left arm connection (positive) on the xyphoid. This produces a first (FI) bipolar chest lead. In addition, the placement of the foot lead (positive) in position V4 provides three bipolar chest leads (FI, FII, FIII) instead of regular leads (I, II, III). This arrangement is used to record more specifically the potentials developed by the delayed right ventricular fibers, covering the infundibulum, the apex, and the diaphragmatic aspect of the right ventricle.

Fontaine 1999

The vertical bipolar lead FI, which is similar to VF, seems to be the most appropriate to record epsilon waves; it also magnifies the atrial potentials. It could be useful in the search for AV dissociation in ventricular tachycardia or to study abnormal atrial rhythms when the P waves are too small on regular leads.

Fontaine to Hurst, Circulation 1998

Clinical studies

In 2010, Wang et al published their study on Epsilon waves detected by various electrocardiographic recording methods: in patients with arrhythmogenic right ventricular cardiomyopathy. In particular they compared the three ECG methods of S-ECG, R-ECG and F-ECG in known ARVD/C patients.

They identified 3 patterns of epsilon waves:

  • (A) wiggle waves
  • (B) small spike waves [B1 – spike upward; B2 – spike downward]
  • (C) smooth potential waves with the QRS duration in V1 exceeding the QRS duration in V3 by at least 25ms.
Patterns of epsilon waves wang et al 2010
Patterns of epsilon waves. Wang et al 2010

They found that

  • The duration and amplitude of epsilon waves detected by F-ECG were longer and larger than those detected by the other 2 ECG recording methods.
  • Epsilon waves are relatively low in sensitivity, manifesting themselves during S-ECG in only 20% to 25% of ARVC patients; and those waves are usually seen in leads V1 through V3.
  • Epsilon waves were found in 38% of all patients using S-ECG and increased that to 50% by using F-ECG.
  • The detection rate of epsilon waves using combined methods of ECG recording was significantly higher than that of S-ECG alone (S-ECG 38%; SF-ECG 56%; and SRF-ECG 66%, P=0.0039).

Clinical examples

Example 1

epsilon waves regular lead placement versus Fontaine lead placement
Comparison of S-ECG versus F-ECG in the ability to detect epsilon waves (arrows). Gottschalk et al 2014

The Fontaine lead placement increases sensitivity of detecting epsilon waves so that they are detected in three leads (FI, FII, FIII) rather than one lead in the regular placement.

Example 2

26 year old male presents to emergency with palpitations, dizziness and diaphoresis., No complaints of chest pain or shortness of breath.

ECG on arrival:

sustained VT with LBBB pattern 1

ECG diagnosis: sustained VT with LBBB pattern, heart rate = 125 bpm and right superior QRS axis (only aVR lead with positive QRS complexes). This atypical axis is a hallmark of VT with focus in apex of right ventricle.

ECG Post cardioversion

sustained VT with LBBB pattern post cardioversion 2

Universal low voltage of QRS complexes. Epsilon wave V2 and lead II. T wave inversion in all precordial leads


Fontaine leads showing epsilon waves in ARVD C 2019
Typical example of arrhythmogenic cardiomyopathy with LV involvement. ε wave (arrows).
Pérez-Riera AR. 2019


Original articles

Fontaine lead in clinical practice

Further reading



the names behind the name

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric 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

BA MA (Oxon) MBChB (Edin) FACEM FFSEM. Emergency physician, Sir Charles Gairdner Hospital.  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 |

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