Ebstein's Anomaly in Disguise: Follow the Cues and the Diagnosis Can Be Made.

Ebstein's anomaly is a congenital defect, which is rarely present in adults with arrhythmias and right heart failure with tricuspid regurgitation. The diagnosis is made by non-invasive cardiac imaging with transthoracic echocardiography or cardiac magnetic resonance imaging. However, mild and atypical anatomical variants require a more specific investigation to make the diagnosis and differentiate it from other pathologies which have a similar presentation, including Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC). We present the case of a 66-year-old gentleman with a history of recurrent admissions due to decompensated heart failure exacerbations, now presenting with gradually worsening dyspnea. An echocardiogram was obtained, showing a thin-walled, dilated, and dysfunctional right ventricle (RV) with severe tricuspid regurgitation due to poor coaptation of the tricuspid leaflets. Although a very distinctive epsilon wave was seen on his electrocardiogram, highly suggestive of arrhythmogenic RV cardiomyopathy (ARVC), which would be enough to explain his presentation and initial echocardiogram; an off-axis plane of the tricuspid valve without any RV aneurysm or dilation of the RV outflow tract was incongruent with this diagnosis. Additional echocardiographic images were determinant to demonstrate both apical displacement and tethering of the septal tricuspid leaflet with an abnormally long anterior tricuspid leaflet, suggestive of Ebstein's anomaly. This diagnosis was confirmed with cardiac magnetic resonance imaging. Mild variants of Ebstein's anomaly, especially in the presence of confounding findings require focused imaging to ascertain the diagnosis. We review these non-traditional findings in trying to differentiate Ebstein's from ARVC.