The "Dub" is generally higher-pitched and shorter in duration than the "Lub." Why?
Why the silence between the Dub and the next Lub? That pause is —the heart’s rest and recharge phase. During this silence, the ventricles are relaxing, filling passively with blood from the atria. No valves are snapping shut. It’s the quietest part of the cycle. what produces the lub dub heart sounds
| Sound | Name | Valve Action | Phase | Pitch | Clinical Significance | | :--- | :--- | :--- | :--- | :--- | :--- | | | S1 | AV Valves (Mitral & Tricuspid) close | Systole (Contraction) | Low, Long | Indicates the start of the pumping phase. | | Dub | S2 | Semilunar Valves (Aortic & Pulmonary) close | Diastole (Relaxation) | High, Short | Indicates the start of the filling phase. | The "Dub" is generally higher-pitched and shorter in