A murmur described as 'machine-like' is associated with which congenital heart defect?

A murmur described as 'machine-like' is associated with which congenital heart defect?

• A. Atrial septal defect
• B. Ventricular septal defect
• C. Patent ductus arteriosus
• D. Atrioventricular septal defect

Answer: (C)

A continuous, machinery-like murmur points to a patent ductus arteriosus. After birth, the ductus arteriosus normally closes, but if it stays open, blood flows from the aorta into the pulmonary artery during both systole and diastole because systemic pressure remains higher than pulmonary pressure throughout the cardiac cycle. That ongoing left-to-right shunt creates a continuous murmur best heard near the left infraclavicular area and is often associated with a widened pulse pressure and bounding pulses from runoff into the lungs. Other defects produce different murmur patterns—for example, a harsh holosystolic murmur from a ventricular septal defect or a systolic murmur with fixed S2 split from an atrial septal defect—so the continuous, machine-like quality is characteristic of a patent ductus arteriosus.

A continuous, machinery-like murmur points to a patent ductus arteriosus. After birth, the ductus arteriosus normally closes, but if it stays open, blood flows from the aorta into the pulmonary artery during both systole and diastole because systemic pressure remains higher than pulmonary pressure throughout the cardiac cycle. That ongoing left-to-right shunt creates a continuous murmur best heard near the left infraclavicular area and is often associated with a widened pulse pressure and bounding pulses from runoff into the lungs. Other defects produce different murmur patterns—for example, a harsh holosystolic murmur from a ventricular septal defect or a systolic murmur with fixed S2 split from an atrial septal defect—so the continuous, machine-like quality is characteristic of a patent ductus arteriosus.