When a doctor listens to the heart of a person with a heart murmur, they may hear a whooshing, swishing, humming, or rasping sound. This is due to rapid, turbulent blood flow through the heart.

An S4 heart sound is a low-pitched sound that occurs toward the end of the diastole. In some cases, an underlying health condition, often one affecting the left ventricle, may cause the S4 heart sound ...