Re-Entry Tachycardia

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Re-Entry Tachycardia
2012-05-16 08:54:03
Re Entry Tachycardia

Re-Entry Tachycardia
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  1. What are the two different forms of tachycardia?
    • Focal Tachycardias
    • Re-Entry Tachycardias
  2. Give examples of Focal Tachycardias:
    • Atrial Tachycardia (inc SVT)
    • Sinus tachycardia
    • Tosade
  3. What are Focal Tachycardias Formed from?
    • Enhanced Automaticity
    • Abnormal Automaticity
    • Triggerred
  4. What are the treatment options for focal tachycardia?
    Treat underlying cause
  5. What types of tachycardia does abnormal impulse conduction give rise to?
    Re-Entry Tachys
  6. Examples of Re-entry Tachycardias are:
    • - Atrial Flutter
    • - AVNRT
    • - AVRT (Assessory Pathways)

  7. What care the prerequisites for re-entry?
    Slow and fast pathway whereby one part has a faster/slower refractory
  8. Explain normal physiological features of the AV node:
    • Fast Pathway with slow refractory
    • Slow pathway with fast refractory
  9. What is this structure known as?
    Triangle of Koch
  10. Explain normal sinus rhythm with respects to the AV node:
    • Conduction comes to the AV node
    • Passes down both the fast and slow pathway
    • Fast pathway conducts quicker to the BoH
    • Slow pathway comes to BoH in refractory and can not conduct
  11. How can a SVE cause a re-entry circuit?
    • Passes to AV node as normal but fast pathway is in refractory
    • Passes down slow pathway which conducts to the Ventricles and back up the fast pathway (retrograde) once it finishes refractory
    • Circuit commenses due to slow pathways fast refractory
  12. Some symptoms of AVNRT include:
    • SOB
    • Fatigue Palpitations
    • Dizziness
  13. How is the retrograde P wave caused and why does it occur at same time of QRS:
    • Fast conduction up the AV node back to atria causes retrograde P wave
    • At same time impuse is sent to ventricles
  14. What happens to the PR interval on AVNRT?
  15. What can be done to stop AVNRT?
    How do they help?
    • Valsava
    • Carotid Sinus Massage

    Increase parasympthetic activity
  16. How does adenosine work?
    Affects calcium dependent cells such as SA and AV node
  17. What drug can cease AVNRT? And what does it effect on?
    Adenosine acts on SA node and AV node
  18. How would you suspect AVNRT on an EP study?
    Atrial to BoH (AH interval)
  19. What is RF ablation and how does it prevent AVNRT?
    Positioned against slow pathway (posterior) and ablated
  20. What rhythm is seen on RF slow pathway ablation?
    Escape rhythm
  21. Why should RF ablation be stopped if non-conducted P wave is seen?
    Close to the AV nodal body