Mechanism of wide fixed split in severe right heart failure

  • First you can review the Mechanism of normal split in second heart sound
  • In severe right heart failure, the right ventricle takes a longer time to eject the blood – hence the wide split
  • Also since it cannot accomodate the increased blood flow during inspiration, there is no increase in the split during inspiration

If you couldn’t grasp the rationale behind it, here’s an example:

  • Imagine the right ventricle to be a plane with 100 seats (seats referring to the capacity)
  • Lets first take the case of a normal right ventricle
  • Imagine that during the weekdays (expiration) about 50 people travel in it
  • But during the weekends (inspiration) about 60 people travel in it (due to increased venous return)
  • Its easy to understand that during the weekends, it takes a longer time for the people to get out of the plane
  • But in the holiday season (right heart failure), the plane (right ventricle) is full during both weekdays and weekends
  • Even though there is more demand for the plane during the weekends, (due to increased venous return) the plane (right ventricle) cannot accommodate any more people (blood)
  • Hence there is no difference in time taken for people to exit from the plane (the time taken to eject the blood is the same)
  • This explains the fixed split
  • Hope I didn’t confuse you with the explanation! If you find any difficulty in understanding this concept, please leave a comment below.


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