Which congenital defect involves an abnormal opening between the atria that causes a heart murmur?

Which congenital defect involves an abnormal opening between the atria that causes a heart murmur?

• A. Patent ductus arteriosus
• B. Coarctation of the aorta
• C. Pulmonary stenosis
• D. Atrial septal defect

Answer: (D)

An opening between the atria creates a left-to-right shunt, so blood from the left atrium flows into the right atrium and then to the lungs. This extra flow increases right-heart and pulmonary circulation volume, causing turbulence that shows up as a systolic murmur. Atrial septal defect classically produces a systolic murmur best heard at the left upper sternal border, and it often comes with a fixed, wide split S2 due to delayed closure of the pulmonic valve from the increased flow. Other congenital defects involve different patterns: a patent ductus arteriosus causes a continuous, machine-like murmur; coarctation of the aorta presents with arterial pulse differences and typically not an atrial opening; pulmonary stenosis causes a harsh systolic ejection murmur at the left upper sternal border with possible right ventricular findings. The combination of an abnormal opening between the atria and a murmur best described as a systolic flow murmur at the left sternal border, plus the fixed split S2 clue, points to an atrial septal defect.

An opening between the atria creates a left-to-right shunt, so blood from the left atrium flows into the right atrium and then to the lungs. This extra flow increases right-heart and pulmonary circulation volume, causing turbulence that shows up as a systolic murmur. Atrial septal defect classically produces a systolic murmur best heard at the left upper sternal border, and it often comes with a fixed, wide split S2 due to delayed closure of the pulmonic valve from the increased flow.

Other congenital defects involve different patterns: a patent ductus arteriosus causes a continuous, machine-like murmur; coarctation of the aorta presents with arterial pulse differences and typically not an atrial opening; pulmonary stenosis causes a harsh systolic ejection murmur at the left upper sternal border with possible right ventricular findings. The combination of an abnormal opening between the atria and a murmur best described as a systolic flow murmur at the left sternal border, plus the fixed split S2 clue, points to an atrial septal defect.