The "lub-dub" is the sound of your heart valves working in perfect synchronization to ensure blood flows in only one direction. It is the rhythmic closing of the heart's internal "gates"—the mitral and tricuspid valves first, followed closely by the aortic and pulmonary valves.
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
The most common abnormal heart sound is a — a whooshing, swishing, or humming sound that replaces or accompanies the normal lub-dub. what is lub dub sound
The lub-dub sound is a masterpiece of biomechanical engineering. Two pairs of valves, closing at precisely the right moment, create a rhythm that sustains your entire body.
These are "whooshing" or "swishing" noises heard between the lub and the dub. They are caused by turbulent blood flow, often due to a valve that doesn't close tightly enough or is too narrow. The "lub-dub" is the sound of your heart
That silence is actually the busiest time for your heart! During the silence after the "dub," the heart muscle is relaxing and the chambers are filling up with blood again, preparing for the next "lub." The heart is never truly resting; it is just cycling through different mechanical jobs.
Think of a river: A calm river is silent. A river flowing over rocks creates a gurgle. Similarly, when a valve doesn't close tightly (regurgitation) or doesn't open fully (stenosis), blood crashes through the narrow opening, creating a turbulent whoosh. It is not the sound of the heart
Not every lub-dub is identical. Here are common, harmless variations:
But what exactly causes these two distinct sounds? Why doesn't the heart make just one sound? And what happens when "lub-dub" turns into something else, like a "whoosh" or a "click"?
: These closures prevent blood from flowing backward into the chambers it just left.
Doctors grade murmurs from 1 to 6. Grade 1 is very faint (hard to hear). Grade 6 is so loud you can hear it without a stethoscope, and you can feel it vibrating on the chest wall (a "thrill").