Origin of the Heartbeat/ECG DSA

Question 1

what is the order of depolarization

Answer 1

SA node -> AV -> bundle of his-> purkinje fibers

Question 2

what is the order of repolarization

Answer 2

“last to depolarize is the first to repolarize”

Question 3

why is there a delay at the AV node

Answer 3

time to allow the ventricles to fill before contracting

Question 4

what are the normal leads called

Answer 4

standard limb leads or bipolar leads

Question 5

where does lead 1 go

Answer 5

Left arm (+) to right arm (-)

Question 6

where does lead 2 go

Answer 6

right arm (-) to left leg (+)

Question 7

where does lead 3 go

Answer 7

left arm (-) to left leg (+)

Question 8

what does lead 1 show

Answer 8

left to right conduction above the heart

Question 9

what does lead 2 show

Answer 9

conduction along the right side on a diagnonal

Question 10

what does lead 3 show

Answer 10

conduction along the left side on a diagonal

Question 11

what lead is at the right leg

Answer 11

the ground

Question 12

how are the unipolar and augemented unipolar leads different

Answer 12

the augmented ones have 1 node active and the other two are used to be the negative instead of 1 pos and 12 neg

Question 13

what is the top right augmented lead called

Answer 13

aVR

Question 14

what is the top left augmented lead called

Answer 14

aVL

Question 15

what is the bottom left augmented lead called

Answer 15

aVF

Question 16

what are the 6 chest leads

Answer 16

V1-6

Question 17

what does the p wave correlate to

Answer 17

SA node and atrial depolarization

Question 18

what does the PR interval correlate to

Answer 18

electrical trip from the SA node to AV node and the resulting pause in the AV node itself

Question 19

what does the QRS complex correlate to

Answer 19

ventricular depolarization

Question 20

what does the T wave correspond to

Answer 20

ventricular repolarization

Question 21

what does the QT interval correspond to

Answer 21

total time that the ventricle is depolarized

Question 22

what does the ST segment correlate to

Answer 22

Absolute refractory period of the ventricles

Question 23

what rate is the standard ekg recorded at

Answer 23

25mm/sec

Question 24

what is the x axis of the ekg show? y axis

Answer 24

time; mV

Question 25

1 horizontal ekg line is how many seconds

Answer 25

0.04

Question 26

1 vertical ekg line is how many volts

Answer 26

0.1 mV

Question 27

what does the QT interval measure

Answer 27

total time that the ventricles are depolarized

Question 28

what does the RR interval measure

Answer 28

HR; 0.6 seconds is 60 bpm, 1 sec is 100 bpm

Question 29

how do you calculate HR from RR interval

Answer 29

1. figure mm between two R waves
2. multiply that by 0.04 sec/square
3. take the inverse and get beat/sec
4. multiply that by 60 to get bpm

60/(0.04*RR)

Question 30

what does the mean electrical axis form

Answer 30

Einthoven’s triangle

Question 31

what is mean electrical axis

Answer 31

vector addition of two leads (0 to 90 normal)

Question 32

what is a mean electrical axis in q1? q2? q3? q4?

Answer 32

left axis deviation; extreme axis deviation; right axis deviation; normal

Question 33

how do the ekg waves and intervals match with cardiac phases

Answer 33

p wave = phase 4
qr = phase 0
rs = phase 1
st = phase 2
t wave = phase 3