**2. Associated anomalies and arrhythmias**

Ebstein anomaly is known to have several additional cardiac manifestations. A patent foramen ovale or atrial septal defect is normally present. The right to left shunting across the defect accounts for the relative hypoxia exhibited in certain patients. RV outflow tract obstruction in the form of anatomical pulmonary atresia occurs in about half of the symptomatic neonates requiring surgical intervention [5]. In the setting of pulmonary atresia, a patent ductus arteriosus is required as the source of pulmonary blood flow [6–8]. Left ventricular non-compaction cardiomyopathy has been noted to be associated with EA. A retrospective study demonstrated that 10 of 61 patients (16%) with EA also had left ventricular non-compaction [7]. This was associated with a higher mortality risk of 30% in those with LVNC compared to 13% with EA alone. Wolff-Parkinson-White (WPW) is present in about 10–30% of cases. In about 20% of cases with WPW, there may be more than two accessory pathways present. The accessory pathways are usually present on the tricuspid valve annulus [9, 10]. Due to large right atrium, EA patients are at risk for atrial tachycardia, atrial flutter, intra-atrial reentrant tachycardia, atrial fibrillation, AV node reentrant tachycardia, and ventricular arrhythmias.
