Still’s murmur (a.k.a. “innocent murmur” or “functional murmur”) refers to a benign flow murmur across the aortic valve from high cardiac output and/or increased contractility (inotropy).

this results in a widely split S2 heart sound that still exhibits inspiratory delay. Note that the murmur of an ASD, discussed below, is also midsystolic; however, it has a fixed split S2.