Which anomaly leads to increased right-sided pressure and eventual cyanosis if not corrected?

Atrial septal defect (ASD) is a congenital heart anomaly characterized by an opening in the interatrial septum, which separates the left and right atria. This defect allows blood to flow from the left atrium to the right atrium due to the higher pressure in the left atrium. As a result, the increased volume of blood returning to the right side of the heart leads to elevated right atrial and pulmonary artery pressures.

Over time, the increased blood flow into the lungs can lead to pulmonary congestion and, if significant, pulmonary hypertension. This chronic pressure overload on the right side of the heart may eventually cause right heart failure and result in cyanosis due to shunting of blood. If the right-sided pressure becomes sufficiently high, it can lead to a reversal of flow through the septal defect, resulting in a right-to-left shunt. This reversal allows deoxygenated blood to enter the systemic circulation, resulting in cyanosis.

Therefore, if left untreated, an atrial septal defect can lead to serious complications related to increased right-sided pressure and cyanosis. This understanding highlights the importance of early detection and management of ASDs to prevent these adverse outcomes.