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Question 1

understand this - it’s not too bad…

sometimes it is important to measure QRS vector to make sure things are all as they should be

Question 2

lead 1 - compairing electrode on right on to electrode on left

lead 2 - compare right arm to left leg (the left leg electorde is the recording one)

lead 3 - left leg to left arm

these 3 give us an idea of the QRS complex

Question 3

1. wilson’s central terminal is the 0 one

Question 4

we can use these 6 ledas as an array around the body to record the action of the heart -

can move the electrodes so they each go through the center of the heart

then we can take our unipolar leads (green lines)

superimposed unipolar and dipolar - this gives us hexaxial lead system

Answer 4

leads are marked at positive side

so lead one at 0

lead two at 60

lead three 120

positive side of aVL at -30

Question 5

1. Can heart rate/heart rhythm be determined from any ECG lead?
2. so what is the benefit of using multiple leads?

Answer 5

1. yes
2. to get estimate of average direction of depolarization of the ventricle

Question 6

1. average direction is towards what?
2. if it is going right and cranial - what might that imply?

Answer 6

1. left ventricle (thickest, biggest)
2. imply a thickened right ventricle

Question 7

1. What is the heart rate?
2. as weight gets bigger?

Answer 7

1. number of beats or complexes/min
2. heart rate slower (and metabolic rate)

Question 8

(Heart Rhythm)

1. Describes origin of what? and somtimes what? what is the normal rhythm of the heart called?
2. What is a generic term indicating slow heart rate? does it indicate origin?
3. What is a generic term for fast heart rate? does it indicate origin?

(Ectoptic complex (beat, focus)

4. where does it originate?
5. can be what or what?

Answer 8

1. impulses; conduction abnormalties; sinus rhythm
2. bradycardia; no
3. tachycardia; no
4. anywhere but SA node
5. premature or late (escape)

Question 9

1. what we we call them if they originate above the Av node?
2. what do we call them if they originiate in one of the ventrciles?

Answer 9

1. supraventricular (note that QRS still looks normal - cause ventricular pathway is normal)
2. ventricular (can’t access normal Av node pathway - takes longer than normal - wider - won’t look like normal QRS complex)

Question 10

understand this

Question 11

(practice time)

1. what is this?

Answer 11

1. premature supraventrciular

Question 12

1. what is this?

Answer 12

1. premature ventricular

Question 13

1. and this?

Answer 13

1. ventricular escape complex

Question 14

1. and here?

Answer 14

1. premature ventricular (because they are different than normals)

Question 15

1. what is this?

Answer 15

Question 16

Answer 16

ventricular premature

Question 17

Answer 17

Question 18

Answer 18

Question 19

1. what happens in primary block?
2. secondary?
3. third?

Answer 19

1. every one of the p waves is conducted - but the PQ (PR) takes a longer time
2. some of the p waves are conducted - but some arents (intermittent)
3. nothing goes through AV node (between atria and ventricle) - hopefully saved by ventricuar escape complexes

Question 20

Answer 20

Question 21

Answer 21

Question 22

(Atrial Fibrillation)

1. what is it?
2. don’t get what waves?
3. ECG characterstics?
4. consequences?

Answer 22

1. chaotic relectrical activity within atrial tissue
2. p waves
3. irregular rhythm (often fast)
4. don’t get effective atrial contraction (don’t get topping off of blood in ventricle)

(sound like shoes in the drier)

Question 23

what does this dog have?

Answer 23

1. atrial fibrillation

Question 24

what’s this

Answer 24

atrial fibrillation (

Question 25

Answer 25

Question 26

(Cardiac Arrhythmias - Mechanisms) 1. arrhythmias arise from distubrances of what three things?

Answer 26

1. impulse formation (automaticity), impule conduction, both