About Video

This is a recording taken from the apex area of a young patient. One can hear the rhythm of S3. Note that there is a good intensity of S1 followed by a short ejection systolic murmur. This is followed by the S2. Careful listening will show a low frequency sound (sounds like “Bum”). It will be noted to occur intermittently. The rhythm sounds like the following: Ha…Two…Bum………….Ha…two…Bum………….S3 is best heard at the apex with the bell since it is a low frequency sound. At the bedside, it may be preferable to turn the patient to the left lateral decubitus position and locate the apex and using the bell listen and see if the cadence of S3 can be heard. The left sided S3 is expected to be heard easier on expiration since there is more flow into the left ventricle during expiration. The right sided S3 for similar reason is expected to be louder on inspiration. However S3 is also affected by the proximity of the apex to the chest. If in some patient the apex happens to get behind the ribs on expiration and becomes palpable only on inspiration in the intercostal space, then in such a patient if S3 were audible, it would be heard on inspiration when the apex is palpable even though it may be a left sided S3. Note that in this recording from this patient, the S3 is heard only intermittently. The reason for this could be the effect of respiration as well as the proximity of the apex to the stethoscope.