ekg - DOC by xiangpeng


									                                 EKG Interpretation
   o P wave—Denotes atrial depolarization (when the atria contract and squeeze blood
     into the ventricles). The presence of a p wave is very important to EKG
   o QRS complex—Denotes ventricular depolarization (when the ventricles contract
     and send blood to the lungs and out the aorta to the body).
   o T wave—Denotes ventricular repolarization (when the ventricles get “charged
     up” and ready to depolarize—an inactive period). Note that there is nothing
     labeled to represent atrial repolarization. This does not mean that atrial
     repolarization does not occur, the wave it causes is simply buried in the QRS
     complex so you can’t see it.
   o PR interval—normal is .12-.20
   o QRS interval—normal is <.10

There are several different “categories of rhythms:”
Sinus Rhythms
           o NSR: all intervals normal, rate 60-100
           o Sinus Tach: same as NSR, rate >100
           o Sinus Brady: same as NSR, rate <60

Atrial Rhythms
       o A-fib: no pwaves (just a squiggly line), irregular, rate 120s-180s
       o A-flutter: no pwaves (saw-tooth pattern), regular, rate 80s-100s
       o *PACs: these are not an actual independent rhythm, but a type of ectopy
          (abnormal beat) that can occur. It is an early beat that has a p wave shaped
          differently than the p waves in the rest of the rhythm.

Ventricular Rhythms
   o Ventricular Tachycardia (VT): Wide, bizarre complexes, no intervals. Rate is
       very fast but difficult to determine because lack of intervals to measure.
       Torsades de Pointes is a type of VT that has a very distinct pattern (you’ll have
       to look in your book, I couldn’t find a picture of it). It is generally the result of
       deficient magnesium.
   o V-fib: Nothing but a squiggly line.
   o *PVCs: Like PACs, not an actual rhythm but an abnormal beat. It’s a wide,
       bizarre complex in the middle of a rhythm (look at a picture in your book). They
       can be unifocal or multifocal. Unifocal PVCs are all the same shape and size,
       while multifocal ones look different. Bigeminy occurs when every other beat is a
       PVC. Trigeminy occurs when every third beat is a PVC.

Junctional Rhythms
   o Junctional: No p waves or inverted p waves, and p wave can come after the QRS.
       Rate 40-60.
   o Accelerated Junctional: Like junctional with a rate of 60-100.
   o Junctional Tachycardia: Like junctional with a rate >100.
   o *PJCs: Another type of abnormal beat. It’s an early beat with either no or an
     inverted p wave.

AV Blocks
  o 1st degree: Only abnormality is that the p-r interval is too long (>.20)
  o 2nd degree type I (Wenkebach or Mobitz I): p-r interval progressively lengthens
      until a QRS is dropped (remember longer, longer, drop…Wen-ke-bach).
  o 2nd degree type II (Mobitz II): p-r intervals are normal, but a QRS is dropped in a
      regular pattern. For example..normal QRS, normal QRS, then one is dropped,
      normal QRS, and so on. This pattern continues. Please review a picture of this in
      your EKG book.
  o 3rd degree: This one can be tricky. The most important thing to know about a 3rd
      degree is that there is no relationship between the atria and ventricular
      rhythms—almost like two separate EKGs stuck together. The atria and
      ventricles are beating independently of each other, thus there is not a true p-r
      interval. The atrial rate is greater than the ventricular rate, and the p waves and
      QRSs are equally-spaced. The best way to think of this one is that the atria are
      doing their job perfectly, so we have normal, equally-spaced p waves. The
      ventricles are getting no signal from the atria, so they kick into escape mode, so
      we have equally-spaced QRS complexes that are usually wide. A picture helps
      with this one too—see your EKG book.

    o SVT: Rate is very fast, usually 150-250. It is difficult to distinguish a p wave
        from a t wave due to the rapid rate. The rhythm is regular and QRS complexes
        are generally narrow. These are very easy to spot and don’t require the logical
        methods the others do.
    o PSVT (paroxysmal): All this means is that the SVT comes and goes in a rhythm,
        it is not the underlying rhythm.
Okay, it is finally time to start interpreting. You must interpret in a logical, methodical
fashion or you will be overwhelmed. So, the best first step is to eliminate as many
answer choices as possible. Give yourself multiple choice, it is much easier. The way to
do that is to see if there is a normal p wave.

If there IS a normal P wave, your answer choices are:
      Sinus rhythms
      AV blocks

If there is NOT a normal P wave, your answer choices are:
     Atrial rhythms
     Ventricular rhythms
     Junctional rhythms
     SVTs (I exclude these in my answer choices because it is so easy to eyeball)

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