KIN 103 REVIEW

• Conducting System of the Heart

  • SA node
  • Internodal Pathways
  • AV node
  • AV bundle
  • Bundle branches
  • Purkinje fibers
• The electrical events precede the mechanical events
• R wave


  Most important
• P wave


  Starts with end of ventricular diastole, before the start of atrial depolarization
• Ventricular walls are contracting

  While depolarization happens
• Ventricular systole


  1. Starts with end of ventricular diastole

  2. Ventricles are still contracted

  3. When the P wave begins, the ventricles relax and the mechanical event starts
• Atrial diastole and systole

  1. Atrial diastole starts before the P wave begins and ends halfway through the P wave

  2. Atrial systole starts halfway through the P wave and ends at the R wave
• Ventricular diastole and systole

  1. Ventricular diastole starts at the R wave and ends at the end of the T wave

  2. Ventricular systole starts again at the R wave and goes to halfway through the P wave
• The septum depolarizes first, then it spreads down and back up the side walls of the heart
• The QRS depolarization shows that the ventricles are starting to contract
• During atrial systole, the atria contract and push blood into the ventricles
• During ventricular diastole, the ventricles are relaxed and filling with blood

  
• During ventricular systole, the ventricles contract and push blood out