12 Lead ECG theory

Question 1

What are the indications for electrocardiography?

Answer 1

-chest pain
-acute myocardial infarction
-pulmonary embolism
-dizziness/syncope
-arrythmias
-drug efficacy
-pre- op

Question 2

What is and ECG?

Answer 2

its a representation of the summation of the heart’s electrical activity recorded from electrodes on the body surface.

Question 3

What is the skin prep for an ECG?

Answer 3

-clean
-abrade (gently take away the top layer of the skin)
-no oils
-shave

Question 4

What are three steps to prepare the patient for an ECG?

Answer 4

-explanation
-relaxation
-details (name, hospital number, DOB)

Question 5

whats the difference between congential and acute heart disease?

Answer 5

congentail-born with it
acute-aqquired it over time

Question 6

What is a diagnostic ECG?

Answer 6

-one you can interpret
-has to be 12 lead minimum

Question 7

Who came up with ECG?

Answer 7

-A.D Waller 1887
-Einhoven 1908
-P, QRS, T

Question 8

How to check machine safety?

Answer 8

check the labels on the machine to check its in date, check for visible damage.

Question 9

what things do you need to prepare for the equiptment?

Answer 9

-paper speed
-calibration
-frequency response
-settings, operator dependent

Question 10

What does the paper speed for an ECG need to be?

Answer 10

25mm/s

Question 11

What is the correct callibration for an ECG?

Answer 11

-sensitivity is 10mm/mV

-the standard calibration signal measures 1mV over 10mm
(output over input)

Question 12

What is the frequency respomse for an ECG?

Answer 12

0.05-150Hz

Question 13

What does a monoriting ECG frequency go up to?

Answer 13

40Hz

Question 14

What are the 4 types of lead systems?

Answer 14

-Bipolar
-Unipolar
-Limb leads
-Chest leads

Question 15

What are the limb lead placements?

Answer 15

lead I-left arm to right arm
lead II - left leg to right arm
lead III- left leg to left arm

(top three leads are bipolar)
(bottom three are unipolar)

aVR- right arm
aVL-left arm
aVF- foot

Question 16

What do bipolar leads measure?

Answer 16

amplifying the difference between two sites

Question 17

what are the different colors for limb leads?

Answer 17

yellow -left arm
red-right arm
black-right foot
green- left foot

Question 18

why dont we measure the right lead in a limb ECG?

Answer 18

beacause the right leg is neutral

Question 19

What are the bipolar leads on a limb ECG?

Answer 19

lead I
lead II
Lead III

Question 20

What are the unipolar leads on a limb ECG?

Answer 20

-lead aVR
-lead aVL
-lead aVF

Question 21

Where are the chest leads/ precordial leads placed?

Answer 21

V1- 4th intercostal RSE
V2-4th intercostal LSE
V3-midway V2-V4
V4- 5th intercostal mid clavicular
V5-left ant axilla at the level of V4
V6-mid axilla at the level of V4

Question 22

What does RSE and Lse mean?

Answer 22

Right sternal edge
left sternal edge

Question 23

what does axilla mean?

Answer 23

Armpit

Question 24

where is the acrominoclavicular joint?

Answer 24

end of right clavicle,helps us determine left anterior axilla

Question 25

What are the colours for the precordial leads?

Answer 25

V1-red V2- yellow V3- green V4-Brown V5-black V6-purple

Question 26

What planes do limb leads look at the heart in?

Answer 26

frontal plane

Question 27

What planes do chest leads look at the heart in?

Answer 27

horizontal plane

Question 28

What surface are leads II,III and aVF on?

Answer 28

inferior surface

Question 29

what surface are leads I and aVL on?

Answer 29

high lateral surface

Question 30

What surface are leads V1- V3 on?

Answer 30

anteroseptal surface

Question 31

What surface are leads V4-V6 on?

Answer 31

anterolateral surface

Question 32

What pole is the left arm?

Answer 32

positive pole

Question 33

What is the hexaxial reference system?

Answer 33

allows us to determine how the heart is lying electrically not physically -determines the hearts electrical axis in the frontal plane

Question 34

what do p waves represent?

Answer 34

atrial depolarisation

Question 35

what do QRS complexes represent?

Answer 35

ventricular depolarisation

Question 36

What do T waves represent?

Answer 36

ventricular repolarisation

Question 37

What are some troubleshooting factors?

Answer 37

-gain -sensitivity and paper speed -artefact -baseline wander -muscle tremor -AC interference -comments

Question 38

When do AC mains occur?

Answer 38

-poor maintenance equiptment

Question 39

What causes a baseline wander?

Answer 39

-someone with chronic obstructive airway disease -poor contact with electrodes -cables being knocked

Question 40

What causes somatic?

Answer 40

-shivering -nervous -fidgeting -not laying comfortably -these muscles will interfere with the ECG

Question 41

what is the equation for large square rate of an ECG?

Answer 41

rate= 300/ R-R intervals in large squares

Question 42

What is the equation for small square rate of an ECG?

Answer 42

rate= 1500/ R-R intervals in small squares

Question 43

Whats the equation for the R wave method?

Answer 43

Number of R waves in a rhythm strip x 6

Question 44

Name the perpendicular leads

Answer 44

I and AVF II and AVL III and AVR