Lub-dub Sounds ((full)) -

Think of your heart as a house with four rooms (chambers) and four doors (valves). To get blood moving in the right direction, those doors must open to let blood through and then slam shut to prevent it from leaking backward. The "lub" and "dub" are the sonic booms of those doors closing. The first sound, "Lub" (clinically known as S1 ), marks the beginning of systole —the moment your heart squeezes blood out to the body.

That longer rest is crucial. It’s the moment when the heart fills up with blood again, preparing for the next "lub." Sometimes, a doctor doesn't hear a clean "lub-dub." Instead, they hear a "lub- shhh -dub" or a "lub-dub- whoosh ." This is called a heart murmur . lub-dub sounds

A sharper, higher-pitched, shorter "dub." Think of your heart as a house with

Spoiler alert: It’s not the heart muscle contracting, and it’s not the blood whooshing around. The first sound, "Lub" (clinically known as S1