ECG

Question 1

two types of cardiac cells

Answer 1

myocardial cells

specialized cells

Question 2

Conductivity

Answer 2

ability to transmit impulses from one area of the heart to another

Question 3

Excitability

Answer 3

(irritability) capability of the cell

to respond to a stimulus

Question 4

Automaticity

Answer 4

capacity to initiate an impulse or stimulus

Question 5

Rhythmicity

Answer 5

property of regularitiy of the intervals at which impulses are formed.

Question 6

Refractoriness

Answer 6

Property of being unresponsive to an impulse

Question 7

Sodium and potassium concentration in and around the cell

Answer 7

potassium is high inside the cell and sodium is high outside the cell

Question 8

The inside of the cell is ____ when at rest or in the polarized state

Answer 8

the inside is negative compared to the outside

Question 9

how the sodium moves into the cell

Answer 9

when the cells are stimulated the cell membrane changes its permeability and allows sodium to move rapidly into the cell making the inside + and the outside negative. this is called depolarization

Question 10

depolarized is ____ inside the cell

Answer 10

positive

Question 11

polarized is ____ inside the cell

Answer 11

negative

Question 12

Refractory periods

Answer 12

absolute refractory Period (heart cant respond-during depolarization)

Relative refractory period (can only respond to a strong stimulus-repolarization is n progress.) (this is the T-wave)

Subnormal period (will respond to weaker stimulus- just before reoplarization is completed)

Nonrefractory period (heart is completely repolarized and ready to respond to a stimulus)

Question 13

SA node rate

Answer 13

60-100

Question 14

AV node rate

Answer 14

40-60

Question 15

Purkinje Fibers rate

Answer 15

20-40

Question 16

Bachmans bundle

Answer 16

pathway from RA to LA

Question 17

what does the p wave represent

Answer 17

atrial depolarization

Question 18

What does the QRS represent

Answer 18

ventricular depolarization

Question 19

unipolar electrode records what

Answer 19

the electrical activity between the positive electrode and the center of the heart

Question 20

a bipolar electrode records what

Answer 20

the electrical activity between the positive and negative terminal

Question 21

which way is the impulse going in an upward deflection

Answer 21

toward the positive electrode

Question 22

which way is the impulse going in a downward deflection

Answer 22

toward the negative electrode (from the positive in a bipolar electrode)

Question 23

list the unipolar chest leads

Answer 23

V1, V2, V3, V4, V5, V6

Question 24

List the bipolar leads

Answer 24

Lead I, Lead II, Lead III

Question 25

List the unipolar leads

Answer 25

aVR, aVL, aVF

Question 26

commonly used monitoring lead

Answer 26

MCL1 (modified chest lead) and Lead II

Question 27

Where are the electrodes in Lead II

Answer 27

+ over the apex of the heart (4-5ics MCL) - right side, MCL 2nd ics

Question 28

Where are the electrodes in Lead I

Answer 28

+ left upper MCL (2ics) | - R upper MCL (2ics)

Question 29

Were are the electrodes in Lead 3

Answer 29

+ Left lower | - Left upper

Question 30

Where are the electrodes in V1 MCL1

Answer 30

+ right lower | -left upper

Question 31

Voltage

Answer 31

measured on vertical axis

Question 32

Duration

Answer 32

measured on the horizontal axis by a series of vertical lines; the interval between vertical lines equals 0.04 second

Question 33

small box

Answer 33

0.04

Question 34

large box

Answer 34

0.20

Question 35

isoelectric

Answer 35

baseline- no electric activity

Question 36

An upright p wave means what

Answer 36

that it is coming from the SA node

Question 37

Normal PRI

Answer 37

0.12 - 0.20 seconds

Question 38

where is the PRI measured

Answer 38

from the start of the P wave to the start of the QRS

Question 39

What does the PRI represent?

Answer 39

atrial depolarization and delay through the AV node

Question 40

QRS complex duration

Answer 40

less than 0.12

Question 41

how to measure the QRS

Answer 41

from the beginning of the QRS (Q or R wave, whichever is present) to the end of the S wave

Question 42

J point

Answer 42

end of QRS and beginning of ST segment.

Question 43

what does the T wave represent

Answer 43

Ventricular repolarization (revcovery) it is normally upright in Lead II

Question 44

What does a U wave indicate

Answer 44

Hypokalemia

Question 45

QT interval represents what

Answer 45

the time it takes for the ventricle to depolarize | and repolarize.

Question 46

Normal QT interval

Answer 46

usually 0.34-0.43 for a quick measure if its within 1/2 of the R-R its probably WNL is based on heart rate. A QTc is corrected by the equation to a heartrate of 60 bpm

Question 47

A prolonged QT does what? what is considered prolonged

Answer 47

increases the risk of lethal arrhythmias and sudden cardiac death QTc >500ms

Question 48

Interpretation of ECG

Answer 48

is there a p for every QRS is the PRI regular QRS wide or narrow what is the atrial rate, what is the ventricular rate

Question 49

calculating HR - big box method

Answer 49

300 / the number of big boxes between QRS complexes

Question 50

Calculating HR - small box method

Answer 50

1500 / # small boxes between QRSs

Question 51

another way to calculate HR

Answer 51

10 multiplied by the # of QRS in 6 seconds

Question 52

Most accurate way to check rate on irregular rhythms

Answer 52

count # of R waves for 1 minute.

Question 53

How do you measure the atrial rhythm? How about Ventricular rhythm?

Answer 53

measuring P to P Measuring R to R

Question 54

How to interpret the P wave

Answer 54

``` is it present? is it upright (in lead II) is there a p for every qrs do all the p waves look alike are the Ps regular do they occur where they should ```

Question 55

How to interpret the P-R interval?

Answer 55

what is the PRI duration (short or prolonged) are the durations consistent across the strip (progressively longer) is there a pattern to the changing PRI

Question 56

How to interpret the QRS?

Answer 56

duration of the QRS? do all of them look the same does it bear a fixed relationship to the P Nl < 0.12

Question 57

Premature v. Escape

Answer 57

``` Premature = early Escape = back up rhythm ``` (Escape rate is based on origin of the impulse)

Question 58

NODAL =

Answer 58

Junctional / escape

Question 59

Characteristics of junctional rhythm

Answer 59

PR interval - regular or absent since the P wave may be absent P wave - pacemaker site is the junction so in lead II the p wave may be inverted before the QRS, buried in the QRS or inverted behind the QRS. PRI (if there is a p wave) PRI will be 0.12 or less

Question 60

Normal junctional rate

Answer 60

40-60

Question 61

Accelerated junctional rate

Answer 61

61-100

Question 62

Clinical signs and symptoms of junctional escape rhythm

Answer 62

Slow regular pulse Often a temporary Dysrhythmia If rate dramatically decreases CO may drop

Question 63

Are junctional rhythms regular

Answer 63

Yes

Question 64

S & S of accelerated junctional rhythm

Answer 64

Usually benign