Monday, 25 October 2010

MRCP revision battle 34.3: The third and fourth heart sounds

Third heart sound

Third heart sound, AKA gallop rhythm, can be perfectly normal in children and young adults.

It is due to passive filling of the ventricles when the atrioventricular valves open.

In the over 40s it is pathological and may indicate:
  • mitral regurgitation
  • VSD
  • CCF
  • constrictive pericarditis

S1          S2  S3

The sound of the 3rd heart sound may be remembered as 'Kentucky' or 'SLOSH-ing in'

Fourth heart sound

A 4th heart sound is caused by atrial contraction against stiff ventricles.

It occurs in:
  • aortic stenosis
  • HOCM
  • hypertension

S4  S1     S2

It can be remembered as 'Tennessee' or  'a STIFF wall'

I thoroughly recommend this website to listen to them

Now away from cardiology and to a bit of pharmacology - sodium valproate....