: Your heart performs this "lub-dub" cycle about 100,000 times a day .
This article explains the complete mechanics behind the lub-dub sound, from the anatomy of the valves to what doctors listen for in a heartbeat.
The "dub" is formally known as the .
The "lub-dub" sound of a heartbeat is the sound of your heart's four valves snapping shut in a timed sequence to keep blood flowing in one direction . The Story of the "Lub" and the "Dub" Imagine your heart is a busy house with four main rooms and two pairs of doors that must never be open at the same time to prevent a "leak" (backflow). The First Sound: "Lub" (S1) As the lower chambers of the heart (the ventricles) fill up with blood from the upper rooms, they prepare for a big push to send that blood to the rest of the body. To make sure no blood accidentally splashes backward into the upper rooms, the
The "lub" is formally known as the .
The "lub-dub" sound of your heartbeat is the sound of your . It is not the sound of the heart muscle contracting, but rather the vibration of the valves and surrounding blood as they close to ensure one-way flow. The Two Sounds
A murmur is a valve closing. It is the sound of turbulent blood flow . what is lub dub sound
(ventricles squeeze, AV valves close) → DUB (ventricles relax, semilunar valves close) → pause (heart fills with blood) → LUB ...
This closure prevents blood from flowing backward into the upper chambers (atria). The "lub" is generally lower-pitched and slightly longer than the second sound. The "Dub" (The Second Heart Sound - S2) The second sound, the , is known as S2 . : Your heart performs this "lub-dub" cycle about
| Sound | Technical Name | What is Closing? | What is Happening? | | :--- | :--- | :--- | :--- | | | S1 | Mitral & Tricuspid Valves | Ventricles contract (pushing blood out). | | Dub | S2 | Aortic & Pulmonary Valves | Ventricles relax (chambers fill up). |
If you’ve ever listened to a healthy heart through a stethoscope, the sound you hear is a familiar, two-beat rhythm: . This is not just a random noise; it is the acoustic signature of your heart valves snapping shut. It is the sound of life itself. The "lub-dub" sound of a heartbeat is the