-
¨Loud S1
- ¨Short PR
- interval (<160 msec)
- ¨Tachycardia or hyperkinetic
- states
¨Mitral stenosis
¨Left atrial myxoma
- ¨Holosystolic mitral
- valve prolapse
-
¨Soft S1
- ¤Long PR
- interval (>200 msec)
- ¤Depressed left
- ventricular contractility
- ¤Premature closure
- of mitral valve ( e.g., acute aortic regurgiation)
- ¨Extracardiac factors
- (e.g., obesity, muscular chest,
- chronic obstructive
- pulmonary disease, large breasts)
-
Mid‐diastolic
sounds
- ¨are, for all practical purposes, either normal or abnormal S3 sounds, and most,
- if not all, late diastolic or presystolic sounds
- are S4 sounds
- ¨Each sound
- coincides with its relevant diastolic filling
- phase
- ¨In sinus
- rhythm, the ventricles receive blood during
- two filling phases
-
The
third heart sound: S3
- ¨Low‐pitched sound produced in the ventricle 0.14 to
- 0.16 s after A2, at
- the termination of rapid filling
- ¨Frequent in
- normal children and in patients with high cardiac output
- ¨In older
- patients an S3 is abnormal
- ¤Impairment of
- ventricular function
- ¤Other conditions
- that increase the rate or volume of ventricular filling
- ¤Bell piece
- of the stethoscope
- ¤Left ventricular
- apex during expiration
¨Right‐sided S3
- ¤Left sternal
- border or just beneath the xiphoid
-
S4
- ¨Low‐pitched,
- presystolic sound
- ¤Associated with
- an effective atrial contraction
- ¤Best heard
- with the bell piece of the stethoscope
- ¤Left lateral
- decubitus position
- ¨Diminished ventricular
- compliance
- ¨Frequently accompanied
- by visible and palpable presystolic
- distention of
- the left ventricle
- ¨S4 is
- generated during the atrial filling phase
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