What is typically indicated by a mid-systolic murmur?

A mid-systolic murmur is commonly associated with a condition known as aortic stenosis. This particular type of murmur occurs during the latter part of systole, which is the phase of the cardiac cycle when the heart contracts and pumps blood out. In aortic stenosis, the left ventricle must work harder to push blood through a narrowed aortic valve, leading to turbulent blood flow. This turbulence produces the characteristic sound of a mid-systolic murmur, which is often best heard at the right second intercostal space or along the carotids.

In contrast, other conditions such as mitral regurgitation and tricuspid regurgitation typically produce holosystolic (or pansystolic) murmurs that occur throughout the entire systolic phase, rather than being restricted to the mid-systole. A ventricular septal defect usually presents with a loud holosystolic murmur as well, due to the shunting of blood from the left ventricle to the right ventricle during the entire systolic phase. Therefore, the presence of a mid-systolic murmur is a key indicator pointing specifically towards aortic stenosis.