Ventricular septal defect murmur characteristics include which finding?

• A. Holosystolic murmur at the lower left sternal border
• B. Continuous machinery murmur at the left upper sternal border
• C. Systolic ejection murmur at the left upper sternal border
• D. Diastolic murmur at the apex

Answer: (A)

Ventricular septal defect causes a left-to-right shunt during systole, producing turbulent flow across the defect that lasts through the whole systole. This gives a harsh holosystolic murmur best heard at the left lower sternal border (often with a palpable thrill). The murmur is typically louder with small defects (higher velocity) and softer with large defects that may have heart failure signs. The other descriptions don’t fit VSD: a continuous machinery murmur at the left upper sternal border points to patent ductus arteriosus; a systolic ejection murmur at the left upper sternal border suggests aortic stenosis or flow murmur; a diastolic murmur at the apex indicates mitral stenosis.