Clin Lab - EKG basics

Question 1

Dimensions for small boxes

Answer 1

1mm x 1mm

Question 2

Dimensions for big boxes

Answer 2

5x5 small boxes

• 5mm x 5mm

Question 3

What is measured on the horizontal axis of EKG?

Answer 3

time

Question 4

Time for 1 small box

Answer 4

0.04 sec (40 ms)

Question 5

Time for 1 big box

Answer 5

0.2 sec (200 ms)

Question 6

Time for 5 big boxes

Answer 6

1 sec (1000 ms)

Question 7

What is measured on the vertical axis of EKG?

Answer 7

voltage (mV)

Question 8

Voltage for 1 small box

Answer 8

0.1 mV

Question 9

Voltage for 1 big box

Answer 9

0.5 mV

Question 10

Voltage for 2 big boxes

Answer 10

1 mV

Question 11

NOTE

Answer 11

most times we don’t talk about amplitude in terms of actual numbers. It’s more of does it look the way it should.

Question 12

Which lead is considered the opposite (upside down) of lead II

Answer 12

aVR

Question 13

Describe visualized of P wave on EKG.

Answer 13

first deflection - smaller, rounded

Question 14

Describe visualized of QRS complex on EKG.

Answer 14

large deflection
- first (-) wave–> Q wave
- first (+) wave–> R wave
- next (-) wave–> S wave

Question 15

Describe visualized of T wave on EKG.

Answer 15

last deflection - wider, rounded wave

Question 16

What is a segment?

Answer 16

a relatively flat (isoelectric) area b/t two deflections

Question 17

What is an interval?

Answer 17

encompasses at least 1 deflection (+ or -) & 1 flat (isoelectric) segments

Question 18

P wave represents

Answer 18

atrial depolarization

Question 19

QRS complex represents

Answer 19

ventricular depolarization

Question 20

T wave represents

Answer 20

ventricular repolarization

Question 21

A typical p wave is created by…

Answer 21

an impulse from the SA node

Question 22

Describe the PR segment

Answer 22

• end of the P wave to start of QRS complex
• all atrial cells are depolarized
• impulse is held by AV node

Question 23

Describe the PR interval

Answer 23

• start of P wave to start of QRS complex
• time it takes for the impulse to travel through the atria & the AV node

Question 24

Describe the QRS complex

Answer 24

rapid depolarization through VA bundle, R&L bundle branches, to the terminal ends of the Purkinje fibers throughout the ventricles

• produced ventricular contraction

Question 25

Are Q waves always present?

Answer 25

No, but can be pathologic in right circumstances

Question 26

Describe the ST segment

Answer 26

- flat area b/t end of QRS and the beginning of the T wave - should be same height has PR segment - all ventricular cell depolarized

Question 27

What is the J point

Answer 27

point of inflection where the S wave ends & the ST segment begins

Question 28

Describe the T wave?

Answer 28

- ventricular repolarization - K+ ions leaving the myocyte returning the cell interior to a (-) charge - spread out compared to ventricular depolarization - smaller height

Question 29

Describe the QT interval

Answer 29

- ventricular contraction; beginning of QRS complex to end of T wave

Question 30

What represents systole on EKG?

Answer 30

QT interval

Question 31

What represents diastole on EKG?

Answer 31

- end of T wave to begining of QRS complex

Question 32

Which is long systole or diastole?

Answer 32

diastole

Question 33

What part of the EKG are electrically silent?

Answer 33

the isoelectric lines - the flat lines b/t all the waves

Question 34

What is it called if there is a 2nd (+) wave after the S?

Answer 34

R' --> RSR'

Question 35

What is the name of the (+) wave after T wave & before P wave?

Answer 35

U wave

Question 36

Time: PR interval

Answer 36

120 - 200ms < 1 big box

Question 37

Time: QRS complex

Answer 37

60 -100ms < 3 small boxes

Question 38

Time: QRS complex gray zone

Answer 38

100 - 120ms

Question 39

QRS complex: abnormal time

Answer 39

>120ms > 3 small boxes

Question 40

QT interval: time

Answer 40

360 - 440 ms

Question 41

QT interval varies by & how is this corrected

Answer 41

HR QTc

Question 42

QTc value for men & women

Answer 42

< 440ms in men < 460ms in women

Question 43

On a 12-lead EKG, how long is each lead?

Answer 43

2.5 secs

Question 44

How long is a rhythm strip if present?

Answer 44

10 seconds