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```									ECG evaluation-
Record your measurements on the write up page (last page) where you will mount your
ECG strip for viewing

Remember to run through this checklist as you first scan any ECG:

   Orient the paper strip right side up

   Identify the paper speed, sensitivity, and confirm that you are reading lead II

   Identify the R waves, then the P to the left, and the T to the right

   Check rate using the R waves and paper mark--Is the heart rate too fast or too
slow?

   Check the R—R interval --Is the rhythm regular or irregular?

   Check the P waves—Are the P waves visible and do they all look alike?

   Check the QRS--- Do the QRS waves all look alike? Are any of the QRS waves
wide or bizarre looking?

   Check the relationship between the P and QRS—Is there a P wave for every
QRS? Is the P-R interval normal and consistent?

As you prepare to write up the measurements, take these steps:

1. Determine rate- there are several methods but try this one

10 or 20 method- usually there are regular hash marks at the top or bottom of the
Count the number of complexes that occur in 3 seconds
At 50 mm/sec paper speed, the hash marks are 1.5 sec apart
At 25 mm/sec paper speed, the marks are 3 sec apart

Multiply the number of complexes in 3 seconds by 20= heart rate
Or     Multiply the number of complexes in 6 seconds by 10= heart rate

2. Determine if rhythm is regular or irregular: check the R-R intervals

Paper and pencil method- take a piece of paper and line up the edge across two R
waves. Mark a notch on the paper at the top of each R wave peak. So you will
have 2 marks on the edge of your paper that shows you how far apart those R
waves are. Use this to compare the spacing between the other R waves. The marks
should line up fairly closely to the other R waves. If not, the rhythm is irregular.

Now find a representative PQRST to make your specific measurements:
3. Evaluate P waves- this gives us information about the atria

Are the P waves visible and do they all look alike?
Are the P-P intervals regular – use the paper and pencil method to check
Record the height and width of a representative P wave
if the P waves are not uniform, note a range of measurements for height and width

4. Evaluate QRS waves- this gives us information about the ventricles

Do they all look alike?
Record the height and width of a representative QRS wave
If the duration (width) is greater than 0.06 sec than there is abnormal conduction
in the ventricles

5. Evaluate P-QRS relationship using the PR interval- this tells us if the atria and
ventricles are working together or if there is a heart block

Is there a P wave for every QRS?
Is there a QRS for every P wave?
Are the P-R intervals all the same?
Record the P-R interval

6. Evaluate T wave- this gives information about the repolarization or relaxation
phase of the ventricles
Sometimes electrolyte problems, calcium imbalances, drug reactions, or
ventricular muscle hypoxia will change the T wave and associated measurements

Record the height of the T wave- it should be no greater than 25% of the R wave
Observe the S-T segment- if it is 0.2 mv above or below the baseline, record it
if below- it is “depressed”, if above- it is “elevated”
Record the Q-T interval width- longer than normal is important information,
especially if the animal is on medication

7. The big picture- look over an entire strip and view for unusual elements, weird
waveforms, patterns, or artifacts.
Artifacts- respiratory, electrical interference, muscle tremors, purring

8. Now you have enough information to know if your patient has a normal rhythm or not!
If you answered no to any of the above questions- there may be an arrhythmia. Plus, any
abnormal measurements give information as to the type of arrhythmia present, possible
causes, and if there is heart enlargement. Neato!!
ECG Lead II in the dog                     Name____________________________

Paper speed is at ______________ sensitivity is at ___________________

Tape ECG strip here

1. Heart rate __________________ Is the heart rate normal or abnormal?______________

2. R-R intervals are regular or irregular?____________________

3. P waves: height____________(max 0.4 mv) width ___________(max 0.04 sec)

P waves are WNL and uniform? _____________________

4. QRS waves: height___________(max 3 mv) width__________(max 0.06 sec)

QRS waves are WNL and uniform?_________________________

5. P-R interval: width______________(0.06-0.13 sec)
(or at 50 mm/sec paper speed: 3-6 1/2 boxes)

Is there a P wave for every QRS? __________

Is there a QRS for every P wave?___________

Are the P-R intervals WNL and uniform?_____________

6. T wave height ____________________

Is the T wave height 25% or less than the height of the R wave?___________

Is the S-T segment isoelectric, depressed, or elevated?_____________________

Q-T interval: width _______________(0.15- 0.25 sec)

Q-T interval is WNL? __________________

7. Any artifacts or unusual waveforms? ___________________________________

8. You now know that this ECG tracing is basically: a. Normal or b. Not perfectly normal

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