Heart Sound Lub Dub -

The lub-dub sound is made up of two distinct sounds:

aortic and pulmonary valves close after the blood has been pumped out, preventing it from flowing back into the heart. Medicine LibreTexts +7 10 sites Heart Murmurs | The Texas Heart Institute® Heart Murmurs. ... Normal heart sounds come in pairs. The sounds are often described as a constant “lub-dub, lub-dub.” The first “... The Texas Heart Institute 17.4C: Heart Sounds - Medicine LibreTexts Oct 14, 2025 —