Splitting

Introduction

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  • Normal splitting 
    • physiology
      • inspiration creates a negative intrathoracic pressure
        • this pulls more blood from the systemic venous circulation into the right heart
        • this also holds more blood in the lungs as well leading to less blood going to the left heart
      • this causes A2 to close earlier (less blood) and P2 to close later (more blood flow) increasing the splitting
  • Wide splitting
    • physiology
      • a decreased ability of the RV to empty blood into the pulmonary circulation resulting in an exaggerated delay in pulmonic valve closure
    • associated conditions
      • states of delayed RV emptying
  • Fixed splitting 
    • physiology
      • shunting of blood from left to right that results in increased right heart volume resulting in a consistent delay in pulmonic valve closure 
      • can lead to pulmonary hypertension if large
    • associated conditions
      • ASD
  • Paradoxical splitting 
    • physiology
      • a decreased ability of the LV to empty blood into the systemic circulation resulting in a delayed closure of the aortic valve
        • the left heart fills more during expiration so splitting occurs during expiration and P2/A2 move closer during inspiration
    • associated conditions
      • states of delayed LV emptying (e.g., aortic stenosis or left bundle branch block)