What kind of heart defect is characterized by a left-to-right shunt?

Atrial Septal Defect (ASD) is a heart defect characterized by a left-to-right shunt because it involves an abnormal opening between the left and right atria. This allows oxygen-rich blood from the left atrium to flow into the right atrium, leading to increased blood flow in the right heart and lungs. The result is typically volume overload of the right side of the heart, which can cause hypertrophy and eventually lead to complications such as pulmonary hypertension if left untreated.

This condition commonly occurs as a congenital defect, meaning it is present at birth. The left atrium typically has higher pressure than the right atrium, and therefore, blood is shunted from left to right. This contrasts with conditions that present with other types of shunts or obstructions, such as coarctation of the aorta or transposition of the great vessels, which do not involve such a mechanism.

Understanding ASD and its hemodynamic effects is essential for recognizing how it affects overall cardiovascular function and for planning appropriate management strategies.