All of the following statements regarding total anomalous pulmonary connection are true except –

Hemodynamics of TAPVC TAPVC results in the pulmonary venous blood reaching the right atrium which also receives the systemic venous blood. This results in volume overload to right atrium -p Right atrial enlargement. Larger volume of blood reaches the right ventricle --> Right ventricle enlargement. The blood flow to the left atrium is through patent foramen ovale or ASD. Because there is mixing of unoxygenated blood from systemic circulation and oxygenated blood from pulmonary circulation in the right atrium —> The oxygen saturation of blood in pulmonary artery is higher or identical to that in Aorta. TAPVC can be divided into : - i) TAPVC with pulmonary venous obstruction Pulmonary venous obstruction results in pulmonary arterial hypertension. Pulmonary obstruction —> T back pressure —> 1' Pulmonary capillary pressure T Pulmonary artery pressure u Because of pulmonary venous obstruction oxygenated blood cannot reach heart —> Cyanosis and CHF during first week of life. ii) TAPVC without obstruction (more common) In TAPVC without obstruction, pulmonary blood flow is high. Patients develops CHF at around 6-8 weeks when the fetal pulmonary resistance falls maximally and pulmonary circulation reaches the maximum. Infracardiac type of TAPVC is always obstructive whereas cardiac and supracardiac type may be obstructive or nonobstructive.