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JAMA Cardiology Clinical Challenge
January 4, 2023

One Beat Is All It Takes鈥擶ide Complex Tachycardia in a Middle-aged Man

Author Affiliations
  • 1Lankenau Medical Center, Main Line Health, Wynnewood, Pennsylvania
  • 2Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
JAMA Cardiol. 2023;8(3):296-297. doi:10.1001/jamacardio.2022.4888

A man in his mid-50s with a medical history of nonspecific T-wave abnormalities on electrocardiogram (ECG) reported new-onset chest discomfort, diaphoresis, and shortness of breath that woke him from sleep. Emergency medical services found him to be in a wide complex tachycardia. He was administered a 150-mg bolus of intravenous amiodarone, which failed to terminate his arrhythmia. He ultimately required synchronized cardioversion with a biphasic direct current shock of 100 J. On arrival to the emergency department, his vital signs were stable. Serum electrolyte levels were within normal range and C-reactive protein was less than 6 mg/dL (to convert to milligrams per liter, multiply by 10). High-sensitivity troponin peaked at 1078 pg/mL. His initial 12-lead ECG is shown in Figure 1A. He continued in sinus rhythm with episodes of nonsustained ventricular tachycardia observed on telemetry, as shown in Figure 1B. Cardiac catheterization revealed patent coronary arteries. Cardiac magnetic resonance imaging was remarkable for a dilated right ventricle with moderately reduced systolic function and transmural late gadolinium enhancement with akinesis and dyskinesis involving the right ventricular (RV) free wall and outflow tract extending to the left ventricular (LV) anterior, septal, and apical segments.

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1 Comment for this article
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Where are the epsilon waves?
james coromilas, MDCM | Rutgers Robert Wood Johnson Medical School
The clinical challenge presented by Sauerwein and colleagues1 nicely illustrates how overlap in clinical phenotype between arrhythmogenic right ventricular cardiomyopathy ARVC) and cardiac sarcoidosis can lead to a misdiagnosis. The initial diagnosis of ARVC was in part based on the presence of epsilon waves (major criteria in the modified Task Force Criteria of 20102). Epsilon waves are defined as reproducible low amplitude signals between the end of the QRS and the onset of the T wave. Even with high magnification of the ECG (figure 1A), I was unable to appreciate an epsilon wave in leads V2 or V3. The low amplitude high frequency deflections in V2 and V3 are within the QRS complex as seen when aligning with the terminal R鈥 of the RBBB in lead V1. Epsilon waves are a reflection of late depolarization of basal epicardial RV myocardium and have low sensitivity and low specificity in the diagnosis of ARVC3 because they are seen in other cardiomyopathies and their identification is limited by variability, ECG filter settings and magnification. One of the minor criteria that were cited was the presence of inverted T waves in leads V1,V2,V3 and V4 in the presence of cRBBB. The specificity of this criteria is low since inverted T waves are present in leads V1-V3 in cRBBB. This led the authors to question the diagnosis of ARVC since the T wave inversion was less evident in the one beat that did not have cRBBB (鈥淥ne beat is all it takes鈥). An epsilon wave was also not present in that beat. I might also argue that there is a hint of a negative T wave in V1 in the non cRBBB beat and that the T wave is not inverted in V4 in the cRBBB beat. While epsilon waves remain aa one of many unique electrocardiographic markers with pathophysiologic significance in the prolific lexicon of electrocardiography, their role in the diagnosis of ARVC should be revisited.

References
1. Sauerwein S, Spears J, Yan GX. One beat is all it takes wide complex tachycardia in a middle-aged man. Clinical Challenge, JAMA Cardiology Aug 14, 2024.
2. Marcus FI, McKenna WJ, Sherrill D, et al. Diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia: proposed modification of the task force criteria. Circulation. 2010;121(13): 1533-1541.
3. Towbin JA, McKenna WJ, Abrams DJ et al. 2019 HRS expert consensus statement on evaluation, risk stratification and management of arrhythmogenic cardiomyopathy. Heart Rhythm 2019; 16 (11) e301-e372.
CONFLICT OF INTEREST: None Reported
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