Cor triatriatum dexter (CTD) is an extremely rare congenital cardiac abnormality and its prompt recognition by transthoracic echocardiography (TTE) is essential for a correct diagnosis.
An 82-years-old woman was admitted to our cardiologic ward for worsening dyspnoea. The physical examination revealed a bilateral lower extremity oedema with elevated jugular venous pressure and hepatomegaly. The ECG showed atrial fibrillation with a heart rate of 70 bpm already treated with beta-blockers and direct-acting oral anticoagulant. TTE revealed a left ventricle with normal dimensions and function, a dilated right ventricle with a mild systolic dysfunction and increased wall thickness, a marked dilation of the right atrium and a tricuspid severe regurgitation. A deeper analysis of the right atrium revealed the presence of membrane partitioning the chamber into two compartments (Figure 1). The separation was incomplete as demonstrated by the flow across the membrane with Color-Doppler technique (Figure 2). The patient was treated using high doses of diuretics with a subsequent clinical improvement. A percutaneous intervention on the tricuspid valve was planned by the Heart Time.
CTD derives from the persistence of the right valve of the sinus venosus resulting in a complete or incomplete fibromuscular band which separates the right atrium into two cavities. The spectrum of clinical manifestations is broad, based upon the degree of separation. In older patients CTD is often asymptomatic and incidentally found during diagnostic imaging examinations. TTE plays a key role in the identification of CTD, as a first-line diagnostic imaging tool. It, also, allows a differential diagnosis with a prominent eustachian valve, chiari network, and thebesian valve. However, in difficult cases a multiparametric approach is required including transoesophageal echocardiogram or cardiac magnetic resonance. Echocardiography has a pivotal role in the prompt recognition of other cardiac abnormalities associated with CTD such as atrial septal defect or patent foramen ovale, right ventricular hypoplasia and Ebstein’s anomaly. In our case, none of these were documented. Atrial fibrillation should be investigated due to severe atrial chamber dilation. A multiplane evaluation of the right atrium and the Color-Doppler technique are helpful to visualize the configuration of the membrane and evaluate the absence of flow disturbances.