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Year 2 Cardiovascular > Review of ECG > Flashcards

Flashcards in Review of ECG Deck (41):
1

what channel contributes to the diastolic depolarization?

funny channel

2

which channel is slow, depolarizing?

calcium

3

which channel is rapid, depolarizing?

sodium

4

which channel is responsible for repolarization?

potassium

5

what is the role of the funny channel? when is it closed?

allows positive charge to enter cell during repolarization / hyperpolarization

depolarization

6

what is the theme of phase 1 of cardiac AP?

early repolarization

7

what occurs during phase 1 of cardiac AP?

sodium channels close
some potassium channels open
repolarization incomplete

8

phase 2 of cardiac AP is due to what ion?

calcium

9

what is the membrane potential of cardiac AP phase 2?

approx zero

10

what occurs during phase 0 of cardiac AP? which ion / channel is responsible?

depolarization

fast sodium channels

11

what is the theme of phase 2 of cardiac AP?

plateau

12

what is the theme of phase 3 of cardiac AP?

rapid repolarization

13

what is occuring during phase 3 of the cardiac AP?

more calcium channels are closing
opening of (more) potassium channels

14

what is the theme of phase 4 of the cardiac AP?

resting membrane potential

15

what is occurring during phase 4 of the cardiac AP? which channels are open?

resting potential maintained until next stimulus

only potassium channels are open

16

which phases are lacking in the nodal AP?

1 and 2

17

which channels open once threshold is reached in nodal AP?

calcium

18

during nodal AP, when do calcium channels open?

upon reaching threshold

19

are there fast sodium channels in nodal AP?

no

20

what occurs after max depolarization in nodal AP? which phase is this?

depolarizatino - potassium channels open

phase 3

21

what is the funny current in nodal AP? what is the result?

progressive reduction in potassium efflux
progressive increase in calcium influx

slowly depolarizes cell

22

what is the normal sequence of depolarization?

SA
atria
AV
His
bundle branches
purkinje
ventricles (septum - apex - ventricular free walls)

23

why does signal slow down at the AV node?

differences in connections between these cells - fewer cells

24

which part of the ventricles depolarize first?

septum

25

what are the bipolar limb leads?

I, II, III

26

what are the augmented unipolar limb leads?

aVR, aVL, aVF

27

what are the horizontal transverse plane chest leads?

V1 - V6

28

where is V1 located?

4th intercostal space, R sternal border

29

where is V2 located?

4th intercostal space, L sternal border

30

where is V4 located?

5th intercostal space, midclavicular line

31

where is V3 located?

between V2 and V4

32

where is V5 located?

in line with V4, anterior axillary line

33

where is V6 located?

in line with V4 and V5, midaxillary line (down from armpit)

34

what does the ST segment correspond to on the ECG?

phase 2 plateau

35

what does the QT segment correspond to on the ECG?

ventricular depolarization and repolarization

essentially the AP

36

what is the physiological correlate of the P wave?

atrial myocyte depolarization - phase 0

37

what is the physiological correlate of the QRS complex?

ventricular myocyte depolarization - phase 0

38

what is the physiological correlate of the PR interval?

all electrical events (depolarization - phase 0s) upstream of ventricular myocytes (atrial myocyte, AV node, bundle, bundle branches, purkinje)

39

what is the physiological correlate of the T wave?

ventricular myocyte repolarization - phase 3

40

what is the physiological correlate of the QT interval?

entire AP for ventricular myocytes (depolarization - plateau - repolarization)

41

what is the physiological correlate of the ST segment?

ventricular myocyte plateau - phase 2