Cardiac Conduction System ECG

• Cardiac Conduction System:

  1. impulse generated in SA node, located at the top of the RA
  2. travels through Bachmanns bundles into the LA and also travels down the internodal tracts to the AV node - delays relay of the impulse to allow atria to contract
  3. impulse relayed to bundle of His, then onto left and right bundle branches, then onto purkinje fibres

  
• Cardiac Conduction System:

  • normally HR can be from 60 to 80 bpm as the SA node is influenced by the SNS, but the PNS dampens the rate
  • once PNS affect is removed, HR can increased up to 100 bpm
  • on an ECG if there is no P wave, we know the impulse was generated at the AV node instead, where the rate is only 40 to 60 bpm
  • if there is a problem with the AV node, the purkinje fibres will generate a impulse at 20 to 40 bpm