What is a common clinical finding in a patient with atrial septal defect?

• A. High blood pressure
• B. Fixed split S2 heart sound
• C. Hyperkalemia
• D. Wheezing

Answer: (B)

Atrial septal defect (ASD) is a type of congenital heart defect that results in an abnormal opening between the right and left atria, leading to a left-to-right shunt of blood. A common clinical finding associated with ASD is the presence of a fixed split S2 heart sound.

In a normal cardiac cycle, the second heart sound (S2) occurs due to the closure of the aortic valve (A2) followed by the closure of the pulmonary valve (P2). The splitting of S2 is usually influenced by respiration; it becomes wider upon inhalation and narrows with exhalation. However, in the case of an ASD, the increased blood flow to the right atrium and subsequently to the right ventricle increases the volume of blood being pumped through the pulmonary valve, leading to a prolonged right ventricular systole. Consequently, the splitting of S2 becomes "fixed," meaning it does not vary with respiration. This fixed splitting is a direct result of the hemodynamic changes caused by the ASD and is a classic auscultatory finding in these patients.

The other options listed have associations that do not align with the typical clinical presentation of ASD. High blood pressure would not be a hallmark finding, hyper