This is a transoesophageal echocardiogram of a 23 year old woman who presented with atrial tachycardia and an indefinite past history remarkable for two episodes of anasarka oedema which responded to albumin supplementation. In previous years the patient had exhibited mild to moderate dyspnoea on exertion (New York Heart Association I–II) and palpitations. Physical examination revealed a supine blood pressure of 100/75 mm Hg and normal S1 and S2. The ECG after cardioversion showed inverted T waves in precordial leads and a deep and wide P wave in lead V1. The signal averaged ECG was normal. Transthoracic and transoesophageal echocardiographic study showed that the patient had normal left heart chambers with severely dilated right chambers, absence of tricuspid and pulmonary valve leaflets, with continuous forward pulmonary flow like in Fontan. On cardiac magnetic resonance imaging no high intensity areas, indicating fatty infiltration of the myocardium, were observed. Cardiac catheterisation showed that the right atrium (RA), right ventricle (RV) and pulmonary artery (PA) appeared as a continuous chamber. No tricuspid or pulmonary valve leaflets were detected and the flow was stagnant. The pressure waveform was similar in the RA, RV, and PA trunk with a pressure value of 26/12 mm Hg.

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This is an unusual case of a congenitally unguarded tricuspid orifice associated with a patent right ventricular outflow tract and severely underdeveloped pulmonary valve leaflets, mimicking the Fontan circulation. Previous reports have shown that a congenitally unguarded tricuspid orifice is associated with pulmonary atresia.