Total anomalous pulmonary venous connection — branching viva

Opening: recognise and confirm

The candidate opens by stating that a cyanosed neonate with pulmonary oedema on day one or two must be considered to have obstructed cyanotic congenital heart disease until proven otherwise, with obstructed total anomalous pulmonary venous connection high on the list alongside transposition and hypoplastic left heart. The normal-sized heart and the pulmonary oedema pattern, rather than a large heart, point away from a volume-load lesion and toward a venous obstruction. ^[7]

The candidate confirms the diagnosis with echocardiography, which is the single diagnostic investigation. It demonstrates the pulmonary venous confluence, the anomalous drainage route, the presence and level of obstruction on doppler, the atrial septum, and the right ventricular load. The chest radiograph gives the first clue but is never diagnostic, and the hyperoxia test does not reliably separate cardiac from pulmonary disease here. ^{[7] [1]}

Branch 1: the Darling classification

The examiner asks for the classification. The candidate answers that the Darling system separates the lesion by where the common pulmonary venous confluence drains. Supracardiac, the commonest at about fifty per cent, drains via an ascending vertical vein to the innominate vein or superior vena cava. Cardiac, about twenty-five per cent, drains to the coronary sinus or directly to the right atrium. Infracardiac, about twenty per cent, drains via a descending vertical vein below the diaphragm to the portal vein, inferior vena cava, or ductus venosus. Mixed, about five per cent, combines two or more patterns. ^[1]