1. ECG

Question 1

What is electrocardiography?

Answer 1

Is the graphic representation of the electrical activity of the heart as it travels through the cardiac conduction system and heart muscle
Sinoatrial node-internodal tracts-atrioventricular node-Bundle of His-Bundle branches-Purkinje fibres

Question 2

Why are ECG’s performed?

Answer 2

to determine HR
Assess cardiac rhythm - need to differentiate normal VS abnormal and dangerous vs harmless
Show conduction abnormalities
aids in the treatment of cardiac arrest

Question 3

How do we read an ECG graph?

Answer 3

This complete complex represents a single heartbeat
How long the electrical impulse takes is shown on the horizontal axis in seconds
The “amount” of electricity is shown on the vertical axis (measured in millivolts (mV). baseline is 0mv

Question 4

What is the P-QRS-T complex?

Answer 4

P-wave: depolarization (contraction) of the atria
QRS complex: Depolarization (contraction) of the ventricles
T-wave: Repolarization (prepping for next contraction) of the ventricles.
Can be either pos or neg wave deflection as long as it doesn’t fluctuate on the same rhythm strip

Question 5

How will the depolarizing wave travel through an animal’s heart?

Answer 5

Cranial to caudal
Left to right
dorsal to ventral

Question 6

How might ECG be measured as positive vs negative?

Answer 6

If depolarizing wave is moving in one direction relative to the way it is being measured, it may be measured as positive
If depolarizing wave is moving opposite relative to the way it is being measures, may be neg

Question 7

What does the veterinary ECG records?

Answer 7

Gives a pos deflection of the P and R waves in the normal small animal ECG
Records the strongest positive reading because it looks @ the electrical activity of the heart in the direction of the wave of depolarization

Question 8

What is our role and importance with ECG?

Answer 8

HR and rhythm are most valuable pieces of info collected from ECG
We are responsible for hooking animal up, calibrating machine and recording results
Like an x-ray, need to exert best judgement on if we’ve prod diagnostic quality or need to repeat
Will need to obtain paper tracings and record all relevant patient info on tracing (ECG rhythm strip is part of legal medical record)

Question 9

What might we need to be able to recognize when doing an ECG?

Answer 9

Need to know abnormalities in tracing are due to patient abnormalities or pathologies or due to patient positioning, movement, mechanical interference
If using EXG to monitor a patient under anesthesia, you do need to be able to calculate HR and to recognize a normal rhythm
Need to know abnormally rhythm (arrhythmia) so appropriate tx started to prevent death

Question 10

What is 50 MM/s and what does it read?

Answer 10

used for SA as they have faster HR
Spreads the complexes out so more detail can be seen
Each sm box is 0.02s
Each lg box is 0.1s

Question 11

What is 25 MM/s and what does it read?

Answer 11

Used on LA with slower HR’s
Compresses the complexes
Half the speed so it takes 2x as long to cover the same distance
each sm box is 0.04
each lg box is 0.2s

Question 12

What are some questions to assess if the ECG is normal?

Answer 12

What is the HR? Is it reasonable for animal’s species, age, and situation
What is the rhythm?
- Are all ventricular complexes of the same configuration (same height/width
Are all QRD complexes preceded by P waves?
Are all P waves followed by QRS complexes
Are all of the P waves of the same configuration? Are they normal for the species and the HR

Question 13

When calculating a HR using an ECG with a regular rhythm. What would 15 small boxes equal for 22 mm/s paper and 50 mm/s paper?

Answer 13

Divide 1500 by the # of small boxes btw two R’s to get bpm
Sm box = 0.04 s
1500/15 = 100bpm
50mm/s is 3000/15=200bpm

Question 14

How do we calculate irregular rhytms on ECG’s?

Answer 14

Calculate an average
count the #’s of QRS complexes in a predetermined time period and multiply the factor
Most common is 6s

Question 15

What are the normal HR’s of k9’s, feels, bovine and equines?

Answer 15

k9 sm - 80-140bpm
lg 60-120 bpm
Fel: 180-220 (lower @ home)
Bovine: Calf 60-120bpm
Adult: 60-80bpm
Equine: Feal 80-120bpm
Adult 28-40bpm

Question 16

What are normal cardian rhythms?

Answer 16

Is there a P for every QRS and a QRS for every P?
Determines that the heart is depolarizing normally, controlled by the Sinoatrial node
Referred to as normal sinus rhythm

Question 17

What is sinus arrhythmia?

Answer 17

HR coordinated with respirations
dec during expiration
Inc during inspiration
Normal in dogs, horses and cattles
abnormal in cats
Normal P wave for every QRs Complex; relatively constant P-R interval

Question 18

What is sinus bradycardia?

Answer 18

Bradyarrhythmia or abnormally slow HR
Can be somewhat normal, but should be monitored and under anesthesia all equipment and depth should be double checked for lvl of depth

Question 19

What is sinus tachycardia?

Answer 19

Tachyarrhythmia or abnormally fast HR

Question 20

What is an AV block and its 3 types?

Answer 20

A delay or interruption in conduction of the electrical impulse - results in slower than normal HR
1st degree - prolonged PR interval
2nd degree - Occasionally missing QRS complexes
3rd - random PR intervals

Question 21

What are the 3 types of AV blocks and which are “normal” vs not?

Answer 21

1st degree - prolonged PR interval. Normal in resting horses or in animals under anesthesia. Also seen with hyperkalemia or cardiac dz
2nd degree - occasionally missing QRS complexes. Can be normal in resting horses or in animals under anesthesia. Also w/ hyperkalemia or cardiac dz
3rd degree - random PR intervals.
NOT NORMAL, req’s tx

Question 22

What are premature complexes?

Answer 22

Complexes that appear earlier than they should if normal conduction paths are followed
Ex. Premature supraventricular complexes (PSC)
Premature ventricular contractions/complexes (PVC)

Question 23

What is a premature supraventricular complex rhythm?

Answer 23

one or more normal QRS complexes closely following the previous QRS complex
Usually have narrower, more normal-looking complexes
P wave abnormalities or absent P waves

Question 24

What are premature ventricular contractions/complexes rhythm?

Answer 24

Usually appear as a very wide complex closely following the previous QRS complex

Question 25

What is atrial fibrillation rhythm?

Answer 25

Irregularly irregular ventricular rhythm
Irregular R-R intervals with no predicatable pattern
QRS morphology is normal
Atrial beat irregularly - extreme rapid contraction of the atria in various sm portions of the atrial wall at any one time. Normal-fast rate
Seen as fine undulations of the base line with no P waves

Question 26

Sre atrial flutter and atrial fibrillation the same thing?

Answer 26

No! Atrial flutter has regular QRS complexes but a saw tooth baseline
Atrial fibrillation is atrium contraction constantly with no P waves

Question 27

What is ventricular fibrillation rhythm?

Answer 27

Extremely rapid contraction of the ventricles in various sm portions of the ventricular wall at any one time
results in a very rapid but ineffective ventricular rate that prods no pulse
will die quickly if CPR or electrical defibrillation is not attempted immediately
undulating baseline
Absense of QRS complexes

Question 28

What is the industry standard for performing an ECG on a small animal?

Answer 28

Place patient in R lat on a non-metallic surface/mat in a quiet room
When using the ECG to monitor during surgery, procedure may dictate positioning (cats/dogs also in sternal)
Nearby electrical equipment should be unplugged to reduce 60-cycle electrical interference
Limbs should be separated by non-conductive material like towel or paper towel
Connect alligator clips to skin
Place sm amount of electrode gel or alcohol @ connection sites
Long term monitoring to clip fur/use sticky pads OR pass electrode wire directly thru skin. (push 20G needle thru skin, pass electrode wire thru needle, remove needle and secure w/ tape

Question 29

What do each color of alligator clips mean in terms of placement?

Answer 29

Red - L hind
Green - R hind
White/Yellow - R front
Black - Left front
Forelimb clips - proximal to olecranon
Hindlimb clip - cranial+proximal to stifle

Question 30

Which of the 6 leads is most commonly used in large vet med?

Answer 30

Lead 2

Question 31

What is the industry standard for performing ECG on a large animal

Answer 31

Lead 2 most common, performed standing
Lead placement: Left arm electrode (+) - near L ventricular apex (L thorax near elbow)
Right arm electrode (-) - in lower third of R jugular furrow or over R shoulder
Ground electrode (N) - anywhere removed from the hear (ex. left shoulder, R dorsal neck area)

Question 32

What are some sayings to remember placement on small animals?

Answer 32

Xmas @ the end of the year (red + green on hind limbs (end of patient)
Snow on trees (White “above” green) (white on R forelimb and G on R hindlimb
Riders are the “right” team to cheer for (green riders goes on the right)
White rhymes with right (White goes on the right side)