EKG Waveforms and Segments

  1. P-wave?
    • atrial depolarization
    • SA node stimulates right atria to contract (up-phase) followed by left atria (down-phase)
    • Repolarization not seen on ECG (within QRS)
  2. QRS complex?
    ventricular depolarization
  3. Q Wave?
    • Downward deflection ALWAYS
    • Depolarization of interventricular septum
    • Used to detect old MI (> 0.04 sec & > 25% of R-wave)
    • Not always present
  4. R & S-waves?
    • R-wave (1st) large upright deflection
    • S-wave negative deflection following the R wave
    • Represent depolarization of R & L ventricles
  5. T- Wave?
    ventricular repolarization
  6. U Wave?
    wave further repolarization of ventricles
  7. PR segment?
    • from beginning to right before the Q wave dip
    • the time required for the impulse to leave the SA node travel through the atria, AV node, bundle of HIS, bundle branches and Purkinje fibers
  8. ST Segment?
    end of ventricular depolarization and ventricular repolarization
  9. QT Interval?
    ventricular depolarization and repolarization
Card Set
EKG Waveforms and Segments