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Monday, October 29, 2012

MS: Heart Sound


Heart Sounds: Stethoscope Listening

Overview of Heart Sounds  (lub-du ; lub, dub )

·         lub - closure of AV valves, onset of ventricular systole
·         dub - closure of semilunar valves, onset of diastole

Ø  Tricuspid valve (lub) - RT 5th intercostal, medial
Ø  Mitral valve (lub) - LT 5th intercostal, lateral
Ø  Aortic semilunar valve (dub) - RT 2nd intercostal
Ø  Pulmonary semilunar valve (dub) - LT 2nd intercostals

S1  - due to closure of the AV(mitral/tricuspid) valves
      - timing: beginning of systole
      - loudest at the apex
       
S2 -  due to the closure of the semi-lunar (pulmonic/aortic) valves
      - timing: diastole
       - loudest at the base

S3Ventricular Diastolic Gallop
         Mechanism: vibration resulting from resistance to rapid ventricular filling secondary to 
         poor compliance
         Timing: early diastole                  
         Location: Apex (LV) or LLSB (RV)
         Pitch: faint and low pitched

S4  - Atrial Diastolic Gallop
Mechanism: vibration resulting from resistance to late  ventricular filling during atrial systole
        Timing: late diastole ( before S1)
        Location: Apex ( LV) or LLSB (RV)
       Pitch: low ( use bell)
  
Heart Murmurs
Murmur - sounds other than the typical "lub-dub"; typically caused by disruptions in flow

Ø  Incompetent valve - swishing sound just AFTER the normal "lub" or "dub"; valve does not completely close, some regurgitation of blood

Ø  Stenotic valve - high pitched swishing sound when blood should be flowing through valve; narrowing of outlet in the open state

Pericardial Friction Rub

Ø  It is an extra heart sound originating from the pericardial sac
Ø  Mechanism: Originates from the pericardial sac as it moves
Ø  Timing: with each heartbeat
Ø  Location: over pericardium. Upright position, leaning forward
Ø  Pitch: high pitched and scratchy. Sounds like sandpaper being rubbed together
Ø  Significance: inflammation, infection, infiltration



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