Epsilon Waves and Preventing Sudden Cardiac Death

Abstract

Introduction: Epsilon waves on electrocardiogram (ECG) are low voltage potentials following the QRS complex representing delayed right ventricular conduction. These are characteristic of arrhythmogenic right ventricular cardiomyopathy (ARVC). This condition has been associated with sudden cardiac death. Case Presentation: We present a 59-year-old female with a family history of sudden cardiac death who was admitted to the hospital for syncope and found to have a subdural hematoma managed with Burr hole drainage. On day 2, the patient had a sudden episode of sustained monomorphic ventricular tachycardia and loss of consciousness requiring cardioversion to sinus rhythm and initiated on amiodarone. Subsequent ECG showed sinus rhythm with incomplete right bundle branch block, T wave inversions and epsilon waves in precordial leads. Transthoracic echocardiogram showed severely dilated right ventricle and reduced ejection right ventricular ejection fraction (RVEF) of 45%. Cardiac MRI showed worsening RVEF of 27% and regional right-ventricular hypokinesia. Additional genetic testing for ARVC was negative. As per Task Force 2010 criteria the patient met at least two major and two minor criteria which confirmed a “definite” diagnosis of ARVC. The patient was continued on mexiletine and metoprolol and advised to avoid endurance exercise. She received a secondary prevention cardioverter-defibrillator and was referred to advanced heart failure specialist for cardiac transplant evaluation. Discussion ARVC involves mutations in the genes coding desmosomes thus causing replacement of the myocardium with fibrofatty tissue. This results in delayed intraventricular conduction allowing for fatal reentrant ventricular arrhythmias. We emphasize the importance of recognizing epsilon waves on ECG which are highly specific to this disease process. The incidence of epsilon waves in ARVC accounts for 30%. Moreover, recognition of LV involvement in patients with ARVC can help identify patients at higher risk of mortality that may go on to benefit with heart transplant evaluation.