The most commonly heard continuous murmur in the newborn is associated with which condition?

• A. Patent foramen ovale
• B. Pulmonary artery stenosis
• C. Ventricular septal defect
• D. Patent ductus arteriosus

Answer: (D)

A continuous “machinery-like” murmur in a newborn points to a patent ductus arteriosus. When the ductus arteriosus fails to close after birth, there is a persistent link between the aorta and the pulmonary artery. Blood continuously flows from the high-pressure aorta into the low-pressure pulmonary artery throughout both systole and diastole, producing a murmur that lasts the whole cardiac cycle and is typically best heard at the left infraclavicular area. PDA is especially common in preterm infants and can be associated with a widened pulse pressure and bounding pulses if significant.

The other conditions produce murmurs with different timing: a patent foramen ovale typically does not cause a continuous murmur; a ventricular septal defect yields a holosystolic murmur; pulmonary artery stenosis causes a systolic ejection murmur.