Wall-to-wall Cardiothymic Silhouette in Neonates

• Ebstein anomaly: Massive right atrial enlargement. Decreased pulmonary blood flow.
• Pulmonary atresia with intact ventricular septum: Massive right atrial enlargement. Decreased pulmonary blood flow.
• Large pericardial effusion: Seen in hydrops fetalis, sepsis, cardiac tumors, thyroid dysfunction, and diaphragmatic hernia into the pericardial sac.
• Atypical large arteriovenous shunts: For example, peripheral arteriovenous malformations or intracardiac arteriovenous malformations (e.g., coronary artery-right heart fistula). Pulmonary vascularity may be normal due to the high pulmonary vascular resistance of newborns.
• Hypertrophic cardiomyopathy in infants of diabetic mothers:
• Cardiac or mediastinal mass mimicking massive cardiomegaly: Rhabdomyoma (e.g., in children with tuberous sclerosis), teratomas, and congenital diaphragmatic hernia (before gas enters the bowel).

References

Donnelly LF, Gelfand KJ, Schwartz DC, Strife JL. The wall to wall heart: Massive cardiothymic silhouette in newborns. Applied Radiology. 1997 December; 26(12).