: As the ventricles begin to contract, the pressure inside them rises rapidly. This pressure forces the blood backward toward the upper chambers (atria), which pushes the mitral and tricuspid valves closed, preventing backflow. The "lub" is the vibration of the valves and the surrounding blood as this door slams shut. The Second Sound: The "Dub" (S2)
The "lub-dub" is a primary indicator of cardiac health. When valves do not close properly or are narrowed by disease, the sound changes. what makes the lub dub sound in the heart
The lub-dub sound is an essential indicator of cardiac function. Abnormalities in the lub-dub sound can indicate underlying cardiac problems, such as: : As the ventricles begin to contract, the