Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Cardio/Pulm Final > Lecture 5: Physiological Basis of the ECG > Flashcards

Lecture 5: Physiological Basis of the ECG Flashcards

1
Q

How many electrodes in an electrocardiogram; how many readings generated?

A
  • 9 electrodes

- Generate 12 readings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is produced on an ECG if there is a difference in voltage between two electrodes?

A

A deflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the ECG measuring?

A

Extracellular potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What 2 factors are necessary to cause a deflection?

A

1) Part of the cardiac excitable tissue is at a different membrane potential than the rest of the heart
2) Current flow can occurs between those two regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What will occur if only the atria and ventricles are of differing potentials?

A

Does not a cause a deflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why does the ECG not report differences between the atria and ventricles?

A

Due to the fibrous cartilage between the atria and ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which direction does lead I look at the heart from?

A

Left to right (left arm (+) to right arm (-))

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

SA node causes atria to depolarize from _____ to _____?

A

Right to Left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is occurring during the PR interval?

A

AV node is delaying the signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

AP phase 2 delays repolarization of ventricles, and is seen as what segment?

A

ST segment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Ventricles repolarize from ______ to ______; seen as which wave?

A

Left to right; T wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which phase of the atrial AP is represented by the P wave?

A

Phase 0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why is no signal seen at the end of the P wave?

A

All of the atrial cells are effectively the same polarity, all depolarized, no voltage difference.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which phase of the ventricular AP is represented by the QRS complex?

A

Phase 0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which phase of the ventricular AP is represented by the T wave?

A

Phase 3 or repolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does a segment represent on the ECG?

A

Duration of single event

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does an interval represent on the ECG?

A

Duration of several events

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the PR segment?

A

End of atrial depolarization until beginning QRS

19
Q

What is the ST segment?

A

End of QRS until beginning of T wave

20
Q

What is the PR interval?

A

Beginning of P wave until beginning of QRS

21
Q

What is the QT interval?

A

Beginning of QRS until end of T wave

22
Q

What would cause a prolonged QT interval?

A

A prolonged phase 2, caused by Ca2+ and K+(b).

23
Q

When determining rate what does the time between the dark lines (bolder) represent?

A

.2 sec

24
Q

When determining rate what does the time between the light lines represent?

A

.04 sec

25
Q

Why use 12 leads?

A

Each lead displays voltage differences in the myocardium seen from different perspectives by different electrodes

26
Q

Which limbs are involved in an aVF?

A

(RA+LA) to LL (+)

27
Q

Which limbs are involved in aVR?

A

(LL+LA) to RA (+)

28
Q

Which limbs are involved in aVL?

A

(LL+RA) to LA

29
Q

How many vectors for chest or precordial leads?

A

V1-V6

30
Q

What makes up Einthoven’s Triangle?

A

Lead I: RA (-) to LA (+)

Lead II: RA (-) to LL (+)

Lead III: LA (-) to LL (+)

31
Q

How do augmented limb leads work?

A

One of the limb leads is assigned a positive polarity and the remaining 2 electrodes are averaged and assigned a negative polarity

32
Q

Chest or precordial leads are not assigned an axis, they are instead assigned?

A

To a certain region of heart and each acts as a positive electrode

33
Q

Which leads predominantly represent the inferior region of the heart?

A

II, III, aVF

34
Q

Which leads predominantly represent the septal region of the heart?

A

V1 and V2

35
Q

Which leads predominantly represent the anterior region of the heart?

A

V2, V3, and V4

36
Q

Which leads predominantly represent the lateral region of the heart?

A

I, aVL, V4, V5 and V6

37
Q

What is the mean electrical axis?

A

Average direction of spreading AP in ventricles

38
Q

What is used for determining the mean electrical axis?

A

Average amplitude of QRS in I and aVF

39
Q

If both lead I and aVF are positive what does this signify?

A

A normal mean electrical axis

40
Q

If lead I is negative, what does this signify?

A

A right axis deviation, regardless if aVF is either positive or negative.

41
Q

If lead I is positive, but aVF is negative what does this signify?

A

A left axis deviation

42
Q

The P wave begins ________contraction of the atria.

A

Before

43
Q

QRS begins ______ ventricular contraction

A

Before

44
Q

T wave begins ________ ventricular relaxation

A

Before

Cardio/Pulm Final (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions