A third heart sound, or S3, is a low-frequency, extra heart sound that may be heard with a stethoscope right after the normal ...

An S4 heart sound cannot be present during atrial fibrillation (atrial kick is required). An S3 heart sound cannot be present in the setting of severe mitral stenosis. An S3 heart sound can be present ...

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 ...