Lub-dub Sound __hot__ [FAST]

The "lub-dub" is far more than a simple noise; it is the sound of the heart's valves working in perfect synchronization to sustain life. By listening to the pitch, timing, and intensity of these sounds, medical professionals can gain critical insights into the health and efficiency of the human heart. nhlbi, nih (.gov)https://www.nhlbi.nih.gov How the Heart Works - How the Heart Beats | NHLBI, NIH

The “lub-dub” is the specific sound of a healthy human heartbeat as heard through a stethoscope. It is the sound of the heart “squeezing” (muscle contraction is silent), but rather the sound of heart valves closing . lub-dub sound

While S1 and S2 are the primary sounds, a thorough review must mention the pathological "third and fourth" sounds. The "lub-dub" is far more than a simple

| Feature | S1 ("Lub") | S2 ("Dub") | | :--- | :--- | :--- | | | Closure of Mitral & Tricuspid valves | Closure of Aortic & Pulmonic valves | | Phase | Marks onset of Systole | Marks onset of Diastole | | Sound Quality | Lower pitch, longer duration | Higher pitch, shorter, sharper | | Best Heard At | Cardiac Apex (5th ICS, MCL) | Cardiac Base (2nd ICS, RSB) | It is the sound of the heart “squeezing”