The powerful lower chambers of your heart (the ventricles) begin to contract. This sudden spike in pressure slams shut the two top valves: the Mitral and Tricuspid valves. These valves separate the upper chambers (atria) from the lower chambers. When they close, they vibrate, creating that thudding "lub" sound.
| Sound | Common Name | Origin | What is happening? | | :--- | :--- | :--- | :--- | | | "Lub" | Closing of the Mitral and Tricuspid valves. | The ventricles contract to pump blood out, and the inlet valves snap shut to prevent blood from flowing backward into the atria. | | S2 | "Dub" | Closing of the Aortic and Pulmonic valves. | The ventricles relax, and the outlet valves snap shut to prevent blood from flowing backward from the arteries into the heart. | lub-dub sounds
The "Lub-Dub" is the sound of your heart valves performing a high-pressure safety check. The "Lub" ensures blood doesn't go backward into the atria, and the "Dub" ensures blood doesn't go backward into the ventricles. When these sounds change, acquire extra beats, or turn into whooshes, it serves as an audible alarm that the plumbing of the heart may need maintenance. The powerful lower chambers of your heart (the
It marks the moment your heart begins to work. The "Dub" (S2): The Sound of Diastole The second heart sound, known as S2 , is the "dub." When they close, they vibrate, creating that thudding
It’s the most famous two-syllable sound on Earth. From the first time a doctor presses a stethoscope to a newborn’s chest, we are taught to listen for the “lub-dub.” But have you ever stopped to wonder what actually creates that iconic sound? Is it the heart beating? The blood moving? Or something else entirely?