17. Which heart sound is also known as the "ventricular gallop"?

A. S1

B. S2

C. S3

D. S4

E. Physiologic split S1

F. Physiologic split S2

The third heart sound (S3), also known as the "ventricular gallop", occurs just after S2 when the mitral valve opens allowing passive filling of the left ventricle. The S3 sound is actually produced by the large amount of blood striking a very compliant left ventricle (LV).