Question

Atrial systole takes place first (during which dup sound produced)and ventricular systole after it (during which lubb sound heard)then why is it said that lubb is first sound followed by dup

Answer 1

Answer:

It said that lubb sound is first caused because Ventricles play the role of pumping the blood away from Heart, hence is considered more important and cardiac cycle is termed to start with that.

Hence, lubb sound is followed by Dup sound.