A murmur is either systolic, diastolic or continuous throughout systole and diastole. Remember: Systole occurs between the S1 and S2 heart sounds, while diastole occurs between S2 and S1.

A midsystolic murmur begins just after the S1 heart sound and terminates just before the P2 heart sound, so S1 and S2 will be distinctly audible. The term midsystolic is preferred to SEM ...