Intro to ECG Part 1

Question 1

movement of the charge:

if a postive charge moves away from the positive electrode, a ____ deflection is created.

Answer 1

a downward deflection.

Question 2

movement of the charge:

if charge is moving, but not directly toward the positive lead, the deflection will be ___

Answer 2

will be smaller.

Question 3

movement of the charge:

if the charge moves toward and then away, a ___ waveform will be created

Answer 3

if the charge moves toward and then away, a BIPHASIC waveform will be created.

Question 4

movement of the charge:

if the charge moves perpendicular to the leads, then a ____ deflection results

Answer 4

then a very very small deflection results.

Question 5

movement of the charge:

when will there be no deflection on the lead?

Answer 5

1. if the charge is not moving
2. if the tissue is very small

Question 6

All 6 limb leads are ___ degreees apart.

Answer 6

30 degrees apart

Question 7

einthoven’s triangle

Answer 7

the sum of all 3 leads is 0

Question 8

positioning of 6 precordial leads

Answer 8

Question 9

which leads are limb leads? Which ones are precordial?

Answer 9

Question 10

Answer 10

Question 11

Answer 11

Question 12

how to calculate the rate in an ECG lead?

Answer 12

To calculate: 300 divided by number of big squares between beats

300/4 = 756 bpm

Question 13

calculate the rate

Answer 13

300/2 = 150

Question 14

there are 3 types of rhythm

Answer 14

 regular

 irregular with a pattern

 irregular with no pattern

Question 15

analyze the rhythm

Answer 15

regular but fast

Question 16

analyze the rhythm

Answer 16

skipped a beat

Question 17

analyze the rhythm

Answer 17

irregular with a pattern

Question 18

analyze the rhythm

Answer 18

irregular with no pattern

Question 19

note:

Question 20

interpret this ECG

Answer 20

Nonexistant P wave– very diminished

Question 21

interpret this ECG

Answer 21

P waves are present, and they are all on the same size and shape. BUT there are not as many QRS segments compared to P segments. There are more.

Question 22

what does it mean if there are P waves without QRS’s?

Answer 22

AV node is not working properly or there is an SA block in the conduction between atria and ventricle.

the P wave indicates atrial depolarization. if there is no QRS, something is wrong with the ventricle. either something isn’t reaching the ventricle or it isn’t contracting

Question 23

what is going on to the P waves? Why is there still a QRS?

Answer 23

These are not P waves– this is baseline garbage. there is no atria conduction. It’s even hard to determine the T wave.

This is atrial fibrillation. Can get QRS wihtout the P wave because there might be a pacemaker somewhere else in the heart that allows the ventricle to receive electricle stimulation even if the SA node is not functioning properly.

Question 24

A p wave inversion can happen if the ___ node is the pacemaker rather than the ___ node.

Answer 24

A p wave inversion can happen if the AV node is the pacemaker rather than the SA node.

Question 25

What are these P waves doing?

Answer 25

P wave is behind the QRS and then going before.

Question 26

how do you tell if the PR interval is short, normal or long?

Answer 26

 Short is less than 3 little squares (<0.12 sec)
 Normal is 3-5 little squares (0.12 to 0.20 sec)
 Long is more than 5 little squares (>0.20 sec)

the PR interval measures conduction through the AV node

Question 27

the PR interval measures conduction through the ____ node

Answer 27

the PR interval measures conduction through the AV node

Question 28

note: if there are more P waves than QRS complexes, then some P waves won’t have a PR interval, because
there will be no “R” from the absent QRS

Question 29

how long is the PR interval?

Answer 29

4.

note: each square is about .04 seconds

Question 30

how long is the PR interval

Answer 30

7 square x 0.04 = 0.28s. it’s a bit long.

Question 31

why is there no PR interval?

Answer 31

Some P waves don’t have PR intervals because there is no QRS

Question 32

how long is the PR interval?

Answer 32

2.5 = short PR interval. PR interval in this one is constant.

Question 33

There is only one question for the QRS complex
for single lead ECG:

Answer 33

Is the width of the QRS complex narrow
(normal) or wide?

Normal QRS is less than 3 little squares (0.12s)

Question 34

causes of a wide QRS:

Answer 34

1. delay through the normal conducting system
2. the beat that is conducted through the cardiac muscle.

A slow conduction/slow moving event will cause a wide QRS. Could be due to diseased conducting system .

Question 35

analyze QRS complex

Answer 35

normal

Question 36

analyze QRS complex

Answer 36

4 units. a bit wide.

Question 37

4 options for a pacemaker

Answer 37

Question 38

if the ventricle is the pacemaker, the QRS will be ___.

Answer 38

will be wide. therefore, a narrow QRS rules out the ventricle .

Question 39

what part of the ECG will be affected if there is a junctional pacemaker.

Answer 39

will not have a normal PR interval.

therefore, a normal PR interval rules out the AV node as a pacemaker. Also rules out the ventricles as the pacemaker because you would see a QRSD elongation

Question 40

What is the pattern for atrial fibrillation

Answer 40

atrial fibrillation is irregular with no pattern. A regular rhythm rules out fibrillation.

Question 41

what is the pattern for ventricular fibrillation?

Answer 41

has no QRS’s. thus, the presence of QRS’s rules out VF

Question 42

Note;

Question 43

inverted P waves usually rule out the ___ node

Answer 43

usually rule out the SA node.