The human heart is often compared to a tirelessly working pump, but it is perhaps better described as a rhythmic percussion instrument. Every minute of every day, it produces a signature "lub-dub" sound that clinicians use as a primary indicator of cardiovascular health.
While many assume these sounds are the result of the heart muscle contracting, the truth is more mechanical. The "Lub": Closing of the Atrioventricular Valves lub-dub sound of heart is caused by