Fouh hea sound is caused by
A fouh sound can sometimes be heard immediately before the first sound when atrial pressure is high or the ventricle is stiff in conditions such as ventricular hyperophy. It is due to ventricular filling and is rarely heard in normal adults.Ref: Ganong&;s Review of medical physiology 25th edition. Page: 542
Closure of AV valves
Closure of semilunar valves
Rapid ventricular filling
Atrial contraction
Cardiovascular system