Lecture 05/06: Basic Concepts of ECG: Lead System, Measurement, Normal Rhythms (Sosa, Estrada) Flashcards Preview

Undeleted > Lecture 05/06: Basic Concepts of ECG: Lead System, Measurement, Normal Rhythms (Sosa, Estrada) > Flashcards

Flashcards in Lecture 05/06: Basic Concepts of ECG: Lead System, Measurement, Normal Rhythms (Sosa, Estrada) Deck (36):
1

Magnitude of potential is dependent on 3 things:

1) strength of the source
2) distance from the electrodes to the dipole
3) angle of line from the electrode to the midpoint of the dipole

2

standard lead system

bipolar lead system. Lead II most often read

3

Lead I lead placement in bipolar lead system

RA -
LA +

4

Lead II lead placement in bipolar lead system

RA-
LL+

5

Lead III lead placement in bipolar lead system

LA-
LL+

6

Augmented Unipolar limb leads

avR (RA+), avL (LA+), avF (LF+)

7

ECG is good for detecting ______ but not as good at detecting _____

rhythm abnormalities; chamber enlargement

8

Positioning animal for ECG

RLAT recumbency with limbs perpendicular to body preferably on mat

9

faster paper speed is good to use when HR is

fast

10

slow paper speed is good for:

rhythm analysis

11

ECG artifact

ECG abnormality not due to cardiac disorder (i.e. electrical interference, purring, trembling). Do NOT change the HR

12

Four basic determinations of ECG

1) heart rate
2) rhythm analysis
3) measurements for analysis of cardiac size
4) MEA

13

coupling interval

interval between normal sinus beat and ensuing premature beat

14

ectopic beat

disturbance of cardiac rhythm, usually because rhythm is being generated from somewhere other than SA node

15

sinus rhythm

normal rhythm with P for every QRS

16

nonconductive P wave

P wave not followed by QRS

17

Supraventricular rhythm

"above the ventricle." narrow, upright in lead II. Uses rapid conduction system. +/- P wave

18

ventricular rhythm

cannot use the rapid conduction system; wide/bizarre rhythm with no related P wave. less than 90% like normal

19

ventricular premature complex

negative premature complex, wide, bizarre, less than 90% like normal

20

supraventricular premature complex

narrow, upright, more than 90% like normal, but premature beat

21

width of P wave relates to:

duration

22

height of P wave relates to:

voltage

23

PR interval

start of P to start of QRS complex

24

QRS width

beginning of Q to baseline after S

25

R wave height

baseline to R peak

26

ST segment (height)

depression or elevation relative to baseline

27

QT interval

from beginning of QRS to end of T

28

ST segment (width)

from end of QRS to beginning of T

29

Can there be ST without S wave?

Yes

30

QT interval varies inversely with:

HR

31

Mean Electrical Axis

average direction that a wavefront of dipoles is moving in the heart. Applied to QRS complex

32

2 methods for determining MEA:

1) Isoelectric lead method (look at lead that is perpendicular to isoelectric lead)
2) Major Deflection Method (look at lead with major deflection. all 6 leads required for this method)

33

Normal MEA range

+30 to +120 degrees

34

Left axis shift range

-90 to +30 degrees

35

Right axis shift range

-90 to +120 degrees

36

Axis shift indicates:

mean depolarization wave had to take a different path to get to lead. (i.e. more mass --> more shift)

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