What characteristic is involved in a ventricular septal defect murmur?

A ventricular septal defect (VSD) murmur is characterized by a harsh and high-pitched systolic murmur. This is due to the turbulent blood flow that occurs as blood flows from the higher pressure left ventricle into the lower pressure right ventricle through the defect during systole. The murmur's intensity and quality can vary depending on the size of the defect and the volume of blood shunted, but it typically presents as a loud, holosystolic murmur that can be heard best at the left lower sternal border.

In conditions like VSD, the harshness of the murmur is attributed to the high velocity of blood flow across the defect, resulting in distinct acoustic features. Systolic murmurs are commonly associated with left-to-right shunts, as seen in VSD, making this characteristic a hallmark finding in the physical examination of such patients.

Other descriptions such as a soft diastolic rumble, continuous murmur, or a click-like sound during diastole would typically be associated with different cardiac anomalies or conditions. This helps to confirm the appropriateness of identifying a VSD with a harsh and high-pitched systolic murmur as characteristic of this type of congenital heart defect.