When Does the Heartbeat's Second Sound Occur?

Amber253

This discussion seeks to explore the timing of the second sound of the heartbeat. When does the second sound occur in the cardiac cycle? What are the contributing factors to the timing of the second sound? How does the second sound differ from the first sound? What can be done to ensure the second sound is heard correctly?

silverfish747

The second sound of the heartbeat, also known as 'S2', is produced at the onset of backward flow of blood through the aortic valve. This occurs shortly after the contraction of the left ventricle and the release of blood into the aorta. This sound is considered the closure of the aortic and pulmonic valves and is the last sound heard in the normal heart cycle. It usually occurs at the end of the 'S1' or first sound of the heartbeat.

blackmeercat1

The second sound of the heartbeat is produced when the left ventricle contracts and pumps blood through the aortic valve into the aorta. This is known as the "lub" portion of the heartbeat, and it typically follows the "dub" portion of the heartbeat, which is produced when the right ventricle contracts and pumps blood through the pulmonary valve into the pulmonary artery. The two sounds together create the "lub-dub" of the heartbeat.