What are the implications and management of an epsilon wave on an electrocardiogram (ECG) in a relatively young individual with or without a known family history of cardiac issues?

Epsilon Wave on ECG: Diagnosis and Management

What is an Epsilon Wave?

An epsilon wave on ECG is a small, low-amplitude deflection occurring immediately after the QRS complex in the right precordial leads (V1-V3), representing a hallmark—though insensitive—sign of arrhythmogenic right ventricular cardiomyopathy (ARVC), a life-threatening inherited cardiac disease that causes sudden cardiac death in young individuals. 1

• Epsilon waves appear as terminal notches in the QRS complex or low-frequency waves occurring after the QRS ends 1
• They are associated with localized QRS prolongation (>110 ms) in right precordial leads V1-V3 1
• Delayed S-wave upstroke (>55 ms) in V1-V2 frequently accompanies epsilon waves 1

Critical Differential Diagnoses Beyond ARVC

While epsilon waves are most strongly associated with ARVC, they can appear in other serious conditions that must be excluded 2:

• Posterior or right ventricular myocardial infarction 2
• Infiltrative diseases including sarcoidosis 2
• Brugada syndrome 2
• Repaired tetralogy of Fallot (acquired ARVC phenocopy) 3
• Hypothermia 2

Immediate Diagnostic Workup

Essential Initial Testing

All young individuals with epsilon waves require comprehensive cardiac evaluation under cardiologist supervision, including echocardiography, cardiac MRI, 24-hour Holter monitoring, and exercise stress testing to establish the diagnosis and assess arrhythmic risk. 1

• Echocardiography: Assess for right ventricular outflow tract (RVOT) dilation, RV wall motion abnormalities, and RV dysfunction 4
• Cardiac MRI: Gold standard for detecting fibro-fatty replacement of myocardium characteristic of ARVC 1
• 24-hour Holter monitoring: Detect ventricular arrhythmias including premature ventricular contractions, couplets, triplets, and non-sustained ventricular tachycardia 1
• Exercise stress testing: May unmask epsilon waves not visible at rest and assess exercise-induced arrhythmias 1, 5

Additional ECG Features Supporting ARVC Diagnosis

Look for these accompanying findings that strengthen the diagnosis 1:

• T-wave inversion in right precordial leads V1-V3 (present in >60% of ARVC cases) 1
• QRS duration >110 ms with right bundle branch block pattern 1
• Premature ventricular contractions with left bundle branch block morphology 1

Clinical Significance and Risk Stratification

Epsilon Waves Predict Specific Cardiac Involvement

Epsilon waves correlate strongly with RVOT involvement and sustained ventricular tachycardia episodes, but do not independently predict sudden cardiac death. 4

• Epsilon wave presence associates with RVOT wall motion abnormalities (P=0.001) and increased RVOT diameter (P<0.0001) 4
• Extension of epsilon waves beyond lead V3 indicates more extensive disease with longer epsilon wave duration (P=0.002) and greater RVOT dilation (P=0.04) 4
• Epsilon wave duration positively correlates with RVOT diameter (r=0.70, P=0.0001) 4
• Patients with epsilon waves have significantly increased risk of sustained ventricular tachycardia (P=0.004) 4

Family Screening is Mandatory

Obtain ECGs from all first-degree relatives, as ARVC is predominantly caused by mutations in desmosomal protein genes with autosomal dominant inheritance. 1

• 76 of 86 patients (88%) with ARVC carry desmosomal mutations 4
• Family history of sudden cardiac death significantly increases risk 1
• Genetic testing should be considered when clinical suspicion is high 1

Management and Sports Participation Restrictions

Implantable Cardioverter-Defibrillator (ICD) Indications

ICD implantation is recommended (Class I) for ARVC patients with documented sustained ventricular tachycardia or ventricular fibrillation who have reasonable expectation of survival with good functional status for >1 year. 1

ICD can be effective (Class IIa) for ARVC patients with extensive disease (including left ventricular involvement), family history of sudden cardiac death, or unexplained syncope when ventricular arrhythmias cannot be excluded. 1

• Syncope in ARVC patients carries 15% per year rate of appropriate ICD intervention 1
• Young age, extensive RV dysfunction, LV involvement, polymorphic VT, and family history of sudden death favor ICD therapy 1

Competitive Sports Restrictions

Athletes with diagnosed ARVC should abstain from all competitive sports due to high risk of exercise-triggered sudden cardiac death. 1

• Sudden death in ARVC is often triggered by exercise 1
• ARVC represents a common cause of sudden cardiac death in young athletes, accounting for up to 25% of athletic sudden deaths in Italian studies 1
• Patients should limit activity to leisure-time physical activities under regular clinical surveillance 1

Medical Therapy

Amiodarone or sotalol can be effective (Class IIa) for treating sustained VT/VF when ICD implantation is not feasible. 1

Catheter ablation can be useful (Class IIa) as adjunctive therapy for recurrent VT despite optimal antiarrhythmic drug therapy. 1

Critical Pitfalls to Avoid

• Do not dismiss epsilon waves as benign: They represent significant structural heart disease requiring immediate evaluation 1
• Do not clear for sports participation without complete workup: Exercise triggers fatal arrhythmias in ARVC 1
• Do not rely on resting ECG alone: Exercise testing may unmask epsilon waves not visible at baseline 5
• Do not overlook exogenous triggers: Anabolic steroids and thyroid hormone supplementation can precipitate fatal arrhythmias in underlying cardiomyopathy 2
• Do not confuse with acute coronary syndrome: ST-segment elevation after cardioversion from VT may mask underlying epsilon waves 6

Long-term Surveillance

Serial ECGs and echocardiography are essential as ARVC is a progressive disease with variable penetrance and age-related expression. 1

• Regular follow-up with cardiologist or electrophysiologist 1
• Repeat cardiac MRI to assess disease progression 1
• Ongoing family screening as relatives may develop disease over time 1