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)
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1
Q

Magnitude of potential is dependent on 3 things:

A

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
Q

standard lead system

A

bipolar lead system. Lead II most often read

3
Q

Lead I lead placement in bipolar lead system

A

RA -

LA +

4
Q

Lead II lead placement in bipolar lead system

A

RA-

LL+

5
Q

Lead III lead placement in bipolar lead system

A

LA-

LL+

6
Q

Augmented Unipolar limb leads

A

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

7
Q

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

A

rhythm abnormalities; chamber enlargement

8
Q

Positioning animal for ECG

A

RLAT recumbency with limbs perpendicular to body preferably on mat

9
Q

faster paper speed is good to use when HR is

A

fast

10
Q

slow paper speed is good for:

A

rhythm analysis

11
Q

ECG artifact

A

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

12
Q

Four basic determinations of ECG

A

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

13
Q

coupling interval

A

interval between normal sinus beat and ensuing premature beat

14
Q

ectopic beat

A

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

15
Q

sinus rhythm

A

normal rhythm with P for every QRS

16
Q

nonconductive P wave

A

P wave not followed by QRS

17
Q

Supraventricular rhythm

A

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

18
Q

ventricular rhythm

A

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

19
Q

ventricular premature complex

A

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

20
Q

supraventricular premature complex

A

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

21
Q

width of P wave relates to:

A

duration

22
Q

height of P wave relates to:

A

voltage

23
Q

PR interval

A

start of P to start of QRS complex

24
Q

QRS width

A

beginning of Q to baseline after S

25
Q

R wave height

A

baseline to R peak

26
Q

ST segment (height)

A

depression or elevation relative to baseline

27
Q

QT interval

A

from beginning of QRS to end of T

28
Q

ST segment (width)

A

from end of QRS to beginning of T

29
Q

Can there be ST without S wave?

A

Yes

30
Q

QT interval varies inversely with:

A

HR

31
Q

Mean Electrical Axis

A

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

32
Q

2 methods for determining MEA:

A

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
Q

Normal MEA range

A

+30 to +120 degrees

34
Q

Left axis shift range

A

-90 to +30 degrees

35
Q

Right axis shift range

A

-90 to +120 degrees

36
Q

Axis shift indicates:

A

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

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