CD Midterm

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CD Midterm
2013-03-05 11:11:21

CD Midterm
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  1. SA Node rate...
    60-100 bpm
  2. AV Node rate...
    40-60 bpm
  3. Bundle of HIS rate...
    20-30 bpm
  4. QT Interval. Normal range?
    From beginning of Q to the end of the T wave. Represents total ventricular activity.  Normal range= 0.44 or >
  5. T wave
    represents ventricular repolarization
  6. ST Segment
    End of the S wave, beginning of the T wave
  7. R & S waves represent?
    R & S waves represent the depolarization of the L & R ventricles.
  8. S Wave...
    Negative waveform that follows the R wave.
  9. R Wave...
    First positive deflection following the P Wave or Q wave (if present).  Always appears as a positive waveform.
  10. Q Wave...
    a negative deflection following the P wave. Always appears as a negative waveform.
  11. QRS Complex.  Normal range?
    • Represents the depolarization of the ventricles and HR.
    • Normal range= 0.06- 0.12
  12. PR Interval.  What is the normal range?
    • From the beginning of the P wave to the beginning of QRS Complex.  Reflects the impulse travel time from the SA node through the AV node, HB, R & L bundles, and into the Purkinje fibers.
    • Normal range= 0.12- 0.20
  13. P wave represents...
    atrial depolarization and spread of impulse across the L & R atria
  14. EKG paper: Small squares?
    Small square: 1mm x 1mm, 0.04 sec
  15. EKG paper: Large squares?
    Large square: 5mm x 5mm, 0.2 sec
  16. Relative Refractory Period
    "Vulnerable Period" because cells are repolarizing and can be stimulated (if stimulus is strong enough) thus possibly resulting in ventricular chaos. Downslope of T wave.
  17. Absolute Refractory Period
    From the onset of QRS to approximately the peak of T wave.  Cells are depolarized and cannot be stimulated.
  18. NSR
    • Normal electrical activity.
    • Impulse originates in the SA node & follows the normal pathway of conduction, resulting in atrial & ventricular depolarization
  19. SB
    SA node discharges impulses fewer than 60 beats/min.  Originates in the SA node and follows the normal pathway of conduction.
  20. Sinus Arrhythmia
    Occurs when the SA node discharges irregularly
  21. Junctional Escape Rhythm
    • Originates from the AV junction & is considered an SV rhythm.
    • 40-60 bpm
    • Usually regular.
  22. Accelerated Junctional Rhythm
    • An ectopic rhythm caused by altered automaticity in the Bundle of His.
    • 60-100 bpm
    • Usually initiated by a few PJCs.
  23. Junctional Tachycardia
    Three or more sequential PJCs occurring at 100/min or more is considered JT   (100-180 bpm).
  24. Paroxysmal junctional tachycardia (PJT)
    • When JT starts & ends suddenly, it is called paroxysmal junctional tachycardia (PJT) & is often initiated by a PJC.
    • When JT is >150 bpm, often difficult to distinguish JT from AT since P waves are not easily seen - then rhythm is called   supraventricular tachycardia (SVT)
  25. Multifocal Atrial Rhythm (MFAR)
    P waves vary in size, shape, & direction across the rhythm strip.  Need to identify 3 different P wave shapes in the same lead to call the rhythm MFAR.
  26. SVT & Atrial Tachycardia (AT)
    SVT can be called atrial tachycardia if a visible P wave (atrial activity) is present.
  27. Paroxysmal Supraventricular Tachycardia(PSVT)
    Describes an SVT that starts & stops suddenly.
  28. Atrial Flutter (A Flutter)
    • An irritable atrial site depolarizes regularly at an extremely rapid rate (250-350 bpm).
    • Results in waveforms that resemble the teeth of a saw or a picket fence.
  29. Atrial Fibrillation (A Fib)
    • Multiple atrial ectopic sites initiate rapid impulses (350-600 bpm) which causes ineffectual atrial contraction or quiver (fibrillate).
    • Results in subsequent decrease in CO, loss of “atrial kick”, & risk of clot formation.