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Activation and Repolarization<br />Overview<br />October 2008<br />
Heart is an “Electrically” Controlled Pump<br />All normal ECG waveforms result from coordinating the pump<br />coordinati...
Contraction Sequence<br />Inside of the heart contracts inwards <br />known as circumferential shortening<br />Diastole<br...
Contraction Sequence<br />And longitudinally<br />Diastole<br />End Systole<br />
Contraction Sequence<br />Then, outside of the heart twists/wrings<br />
Contraction Sequence<br />In addition to the inside  outside sequence, there is <br />an anterior  posterior sequence <b...
Relaxation Sequence<br />(Mostly) opposite to contraction<br />Outside of the heart untwists<br />associated with rapid su...
Electrical Sequences<br />Follow (cause!) mechanical sequences<br />Electrical activation (depolarization) of the heart is...
Activation<br />In vivo canine heart<br />TOP<br />MID<br />BOT<br />
Wigger’s Diagram<br />
Heart Cells and Dominoes<br />Dominoes all standing = no current<br />-<br />+<br />V=0<br />
Heart Cells and Dominoes<br />They start falling – current flows<br />-<br />+<br />V=5<br />
Heart Cells and Dominoes<br />All down – no current flows<br />-<br />+<br />V=0<br />
Heart Cells and Dominoes<br />Some start standing – current flows<br />-<br />+<br />V=5<br />
Heart Cells and Dominoes<br />Notice that voltage depends on where<br />we measure<br />+<br />-<br />V=-5<br />
What about activation potentials?<br />Before wave reaches epi.<br />
What about activation potentials?<br />After wave reaches epi. - simulations<br />
Activation & Repolarization<br />Comments?<br />
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Ekg club repolarization

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Made available to EKG Club for educational purposes. Slides developed by Hopenfeld.

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Ekg club repolarization

  1. 1. Activation and Repolarization<br />Overview<br />October 2008<br />
  2. 2. Heart is an “Electrically” Controlled Pump<br />All normal ECG waveforms result from coordinating the pump<br />coordinating contraction of the pump (QRS complex)<br />coordinating relaxation of the pump (ST segment/T wave/U wave)<br />hold<br />relax<br />contract<br />
  3. 3. Contraction Sequence<br />Inside of the heart contracts inwards <br />known as circumferential shortening<br />Diastole<br />End Systole<br />
  4. 4. Contraction Sequence<br />And longitudinally<br />Diastole<br />End Systole<br />
  5. 5. Contraction Sequence<br />Then, outside of the heart twists/wrings<br />
  6. 6. Contraction Sequence<br />In addition to the inside  outside sequence, there is <br />an anterior  posterior sequence <br />apical (bottom)  basal (top) sequence <br />
  7. 7. Relaxation Sequence<br />(Mostly) opposite to contraction<br />Outside of the heart untwists<br />associated with rapid suction of blood back into heart<br />Then inside of the heart relaxes<br />Basal (top) to apical (bottom) relaxation<br />However, the anterior  posterior contraction sequence is the same (not opposite) as the relaxation sequence<br />
  8. 8. Electrical Sequences<br />Follow (cause!) mechanical sequences<br />Electrical activation (depolarization) of the heart is from the inside out<br />Repolarization of the heart is from the outside in (T wave)<br />
  9. 9. Activation<br />In vivo canine heart<br />TOP<br />MID<br />BOT<br />
  10. 10. Wigger’s Diagram<br />
  11. 11. Heart Cells and Dominoes<br />Dominoes all standing = no current<br />-<br />+<br />V=0<br />
  12. 12. Heart Cells and Dominoes<br />They start falling – current flows<br />-<br />+<br />V=5<br />
  13. 13. Heart Cells and Dominoes<br />All down – no current flows<br />-<br />+<br />V=0<br />
  14. 14. Heart Cells and Dominoes<br />Some start standing – current flows<br />-<br />+<br />V=5<br />
  15. 15. Heart Cells and Dominoes<br />Notice that voltage depends on where<br />we measure<br />+<br />-<br />V=-5<br />
  16. 16. What about activation potentials?<br />Before wave reaches epi.<br />
  17. 17. What about activation potentials?<br />After wave reaches epi. - simulations<br />
  18. 18. Activation & Repolarization<br />Comments?<br />

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