A 7-year-old adopted boy presents to the emergency department after fainting. He just switched from being home-schooled to public school and joined the basketball team. He has fainted several times during basketball practices. He did not sustain any injuries or have any prodromes prior to these episodes. He is usually unconscious for less than a minute. He is otherwise healthy and has met all developmental milestones. He does not currently take any medications. His temperature is 97.6°F (36.4°C), blood pressure is 104/54 mmHg, pulse is 100/min, respirations are 19/min, and oxygen saturation is 98% on room air. Physical exam reveals a well-appearing and playful boy. An ECG is performed as seen in Figure A. An echocardiogram is ordered and pending. Which of the following is the most likely diagnosis?
Brugada syndrome
Wolff Parkinson White syndrome
Hypertrophic obstructive cardiomyopathy
Arrhythmogenic right ventricular dysplasia
Arrhythmogenic right ventricular dysplasia
This adopted pediatric patient is presenting with recurrent syncope and an ECG demonstrating an epsilon wave and T wave inversions, which are concerning for arrhythmogenic right ventricular dysplasia.

An epsilon wave is a small positive deflection at the end of the QRS complex. This is an ominous finding and suggests a diagnosis of arrhythmogenic right ventricular dysplasia (ARVD) though it may also be seen in other infiltrative diseases such as sarcoidosis or after ischemic events. ARVD is an autosomal dominant condition where there is fatty infiltration of the right ventricular wall predisposing the patient (classically younger patients) to sudden cardiac death from lethal ventricular dysrhythmias. The epsilon wave is the most specific finding; however, other findings include T wave inversion in V1-V3 or a left bundle branch appearance with frequent premature ventricular complexes among other possibilities. This is a potentially lethal diagnosis and requires management with antiarrhythmics (such as beta-blockers or amiodarone) and the placement of an implantable cardioverter-defibrillator.

Kayser et al. review AVRD. They note the presentation and management of ARVD and how it may present initially only with syncope. Cardiac arrest is a possible presentation as well. They recommend early detection and treatment with an implantable cardioverter-defibrillator to prevent death in this population.

Figure/Illustration A is an ECG with an epsilon wave (red arrow) and inverted T waves in V1/V2 (blue arrows) concerning for ARVD.

Incorrect Answers:
Answer B: Brugada syndrome is an autosomal dominant mutation in cardiac ion channels that presents with a possible right bundle branch pattern with ST segment elevation in V1-V3 or ST coving in these same leads. It may present with syncope.

Answer C: Hypertrophic obstructive cardiomyopathy presents with syncope, sudden death, or cardiac arrest in a young patient associated with exertion or dehydration. It can cause obstruction of the left ventricular outflow tract. A systolic murmur can be heard on cardiac auscultation and echocardiography can confirm the diagnosis. ECG will demonstrate large voltages in V1-V5.

Answer D: QT prolongation can lead to torsades des pointes which presents with twisting of the QRS complexes around an isoelectric baseline. It may present with syncope, hemodynamic instability, or cardiac arrest. Medications, infection, and congenital conditions may prolong the QT interval.

Answer E: Wolff Parkinson White syndrome presents with a delta wave on ECG or a slurred upstroke of the QRS complex. It may cause syncope and evolve into other dysrhythmias including supraventricular tachycardia and ventricular tachycardia.

Bullet Summary:
Arrhythmogenic right ventricular dysplasia (ARVD) may cause syncope or cardiac arrest, and presents on ECG with an epsilon wave.