Feature article

An epsilon wave on electrocardiogram

Daniel B Petrov, consultant cardiologist


A 39 year old man with no history of heart disease was admitted with symptoms of palpitations and weakness lasting for several hours. An electrocardiogram (ECG) showed a wide complex tachycardia with left bundle branch block morphology, consistent with sustained ventricular tachycardia of right ventricular origin. Because of continuing haemodynamic instability, the patient was cardioverted to sinus rhythm with a single 200 J shock. The post-cardioversion ECG (fig 1) showed inverted T-waves in leads V1-V3, with QRS complex duration of 112 ms, and prolonged S-waves upstroke of 55 ms. Increased amplitude ECG showed waves with a small spike upward in lead V3 (fig 2, arrows), which represent characteristic epsilon waves. The patient reported no family history of sudden cardiac death or arrhythmias.

Fig 1

Post-electrocardioversion ECG, with repolarisation changes in leads V1-V3

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Fig 2

Increased amplitude ECG showing epsilon waves (arrows) in lead V3

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What disease is the epsilon wave indicative of?

Answer

The epsilon wave is a specific ECG finding for arrhythmogenic right ventricular cardiomyopathy (ARVC), which is the second most common cause of unexpected sudden cardiac death in young people after hypertrophic obstructive cardiomyopathy.

Discussion

Arrhythmogenic right ventricular cardiomyopathy is an inherited heart muscle disease that predominantly affects the right ventricle. The prevalence of ARVC has been estimated at approximately 1 in 5000 in the population.1 In a series of sudden cardiac deaths in young adults, ARVC was the cause of death in 2%-5%.2

Other possible causes of ventricular tachycardia in young people with no previous cardiovascular disease are cardiac channelopathies (Long QT, Short QT syndromes), catecholaminergic polymorphic VT, and Brugada syndrome.

The first presenting symptom is sudden onset of ventricular tachycardia. There is no single diagnostic test for ARVC. Diagnosis is made using a combination of clinical, ECG, and radiological features. The 12-lead surface ECG can play a key role in the diagnosis of ARVC as most subjects with ARVC have some ECG changes. The most common finding is T-wave inversion in lead V1-V3, but this is non-specific and can be considered a normal variant in women and children under 12. The presence of epsilon waves, however, is considered to be a major diagnostic criterion in ARVC, but it is very difficult to identify patients who are likely to have this wave; electrocardiographic epsilon waves are seen in only 30% of all cases of ARVC.3 The epsilon wave is a small deflection buried in the end of the QRS complex and represent a delay in the depolarisation of the right ventricular free wall.

Patient outcome

Cardiac echocardiogram, coronary angiography with right ventriculography, and magnetic resonance imaging confirmed the diagnosis of ARVC. The patient was treated with an implantable cardioverter defibrillator and discharged on amiodarone.

Learning points

  • 1. Identification of an epsilon wave on a standard 12-lead ECG is a simple, inexpensive initial way to assess patients for ARVC.

  • 2. ARVC is the second most common cause of unexpected sudden cardiac death in young people, after hypertrophic obstructive cardiomyopathy.

Notes

  1. Competing interests: I have read and understood the BMJ policy on declaration of interests and declare that I have no competing interests.
  2. Patient consent obtained.
  3. Provenance and peer review: not commissioned; externally peer reviewed.

References

  1. P KièsM BootsmaJ BaxMJ SchalijEE van der Wall. Arrhythmogenic right ventricular dysplasia/cardiomyopathy: screening, diagnosis, and treatment. Heart Rhythm2006;3:225-34. 10.1016/j.hrthm.2005.10.018 16443541
  2. RJ Francés. Arrhythmogenic right ventricular dysplasia/cardiomyopathy. A review and update. Int J Cardiol2006;110:279-87. 10.1016/j.ijcard.2005.07.004 16099519
  3. C GemayelA PellicciaPD Thompson. Arrhythmogenic right ventricular cardiomyopathy. J Am Coll Cardiol2001;38:1773-81. 10.1016/S0735-1097(01)01654-0 11738273

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