Splitting

Question 1

Normal splitting

Answer 1

Inspiration => 
drop in intrathoracic pressure => 
increase in venous return to the RV => 
increased RV stroke volume =>
increased  RV ejection time =>
delayed closure of pulmonic valve

Low pulm impedance (increased capacity of pulm circulation) also occurs during inspiration, which contributes to delayed closure of pulmonic valve.

Question 2

Wide splitting

Answer 2

Conditions that delay RV emptying:

1) pulmonic stenosis
2) R bundle branch block

Delay in RV emptying causes delayed pulmonic sound (regardless of breath).

An exaggeration of normal splitting

Question 3

Fixed splitting

Answer 3

Seen in ASD
=> L to R shunt
=> RA and RV volume
=> increased flow through pulm valve such that,

regardless of breath, pulmonic closure is greatly delayed

Question 4

Paradoxical splitting

Answer 4

Conditions that delay LV emptying

1) Aortic stenosis
2) L bundle branch block

Normal order of valve closure is reversed so that P2 sound occurs before delayed A2 sound.

Therefore, on inspiration, P2 closure later and moves closer to A2, thereby “paradoxically” eliminating the split.