A murmur that is early-to-mid systolic, best heard at the lower sternal border and disappears with position change is likely what kind of murmur?

An early-to-mid systolic murmur that is best heard at the lower sternal border and disappears with position change is characteristic of an innocent flow murmur. Innocent murmurs, also known as functional murmurs, are common in children and often result from increased blood flow across the valves during periods of rapid growth or increased physical activity.

The timing of the murmur, mentioned as early-to-mid systolic, indicates that it occurs during the heart’s contraction phase when blood is ejected into the aorta. This is typical of innocent flow murmurs. The location at the lower sternal border further supports this characteristic, as innocent murmurs often have this anatomical correlation.

Additionally, the fact that the murmur disappears with position change is another hallmark of an innocent murmur. Many innocent murmurs can vary in intensity depending on the individual’s posture or activity level. For example, when a patient moves from a supine to an upright position, or vice versa, the change in blood flow dynamics due to gravity alters the hemodynamic conditions, often leading to the murmur disappearing or significantly decreasing in intensity.

Overall, these features—systolic timing, location at the lower sternal border, and variability with position—strongly indicate