Which murmur is described as a continuous murmur with equal intensity in both systole and diastole, heard in the left clavicular region with a harsh, machine-like sound?

• A. Patent Ductus Arteriosus
• B. Aortic stenosis
• C. Mitral regurgitation
• D. Tricuspid regurgitation

Answer: (A)

A continuous, machinery‑like murmur heard best at the left infraclavicular area with equal intensity in systole and diastole points to patent ductus arteriosus. When the ductus arteriosus remains open after birth, blood flows from the aorta into the pulmonary artery throughout the entire cardiac cycle, producing a murmur that persists in both phases and is often loudest near S2. This pattern and location are distinctive for PDA.

In contrast, aortic stenosis is a systolic ejection murmur best heard at the right upper sternal border and does not persist into diastole. Mitral regurgitation and tricuspid regurgitation produce holosystolic murmurs—at the apex and left lower sternal border, respectively—and do not have a continuous, machine-like quality.