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Flashcards in Chapter 3 Deck (198)
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1

What can result from blockage of the RCA?

Inferior wall MI and/or disturbances in AV nodal conductions

2

Occlusion of what artery is called the widow maker?

Occlusion of the left main coronary artery

3

What can result from blockage of the circumflex artery?

lateral wall MI
in some patients, occlusion of the circumflex can also lead to a posterior wall MI

4

increased blood concentration of what electrolytes will decrease automaticity?

Decreased sodium, potassium and calcium

5

decreased concentrations of what electrolytes will increased automaticity?

K+ and Ca2+

6

What is the term that describes the ability of cardiac muscle cells to respond to an external stimulus, such as that from a chemical, mechanical or electrical source?

Excitability (irritability)

7

What is the term that describes the ability of a cardiac cell to receive and electrical impulse and conduct it to an adjoining cardiac cell?

Conductivity

(Via intercalated disks)

8

What's the term that describes the ability of myocardial cells to shorten, thereby causing cardiac muscle contraction, in response to electrical stimuli

Contractility

9

The state when the inside of a cell is more negative than the outside of the cell

Polarized state

10

What causes depolarization

movement of sodium into the cell

11

Where does depolarization occur in the heart

depolarization proceeds from innermost later of the heart to the outermost layer (endocardium --> Epicardium)

12

What on the ECG represents ventricular repolarization?

ST segment and T wave

13

what occurs after the relative refractory period and allows a weaker-than-normal stimulus to cause cardiac cells to depolarize?

Supranormal period

seen at the end of the T wave
- because the cell is more excitable than normal, dysrhythmias can develop during this period

14

What's the primary pacemaker and what's its intrinsic rate?

SA node, 60-100 bpm

15

What are the bpm of the different pacemakers?

SA node: 60 - 100 bpm
AV junction: 40 - 60 bpm
Purkinje fibers: 20 - 40 bpm

16

What heart surface is viewed from the three standard limb leads?

Lead I - lateral heart
Leads II and III - inferior heart

17

What heart surface is viewed from each of the augmented leads?

aVR - non
aVL - lateral
aVF - inferior

18

Where is lead V1 placed?

4th intercostal space on the R next to the sternum

19

Where is lead V2 placed?

4th intercostal space on the L next to the sternum

20

Where is lead V4 placed?

left midclavicular line in the 5th intercostal space

21

If time doesn't permit obtaining all of the R chest leads, which is the lead of choice?

V4R

22

What leads view the inferior surface of the heart?

II, III, aVF

23

What leads view the septal surface of the heart?

V1, V2

24

What leads view the anterior surface of the heart?

V3, V4

25

What leads view the lateral surface of the heart?

I, aVL, V5, V6

26

how much time does a 1mm box stand for?

0.04 second

27

how much time does a large box stand for?

0.2 seconds (contains 5 x 1 mm boxes)

28

how many mV does the height of one block correspond to?

0.1 mV for each 1 mm box

29

What signifies a pathological Q wave?

Abnormal Q waves are more than .04 s in duration or more than one-third the height of the following R wave in that lead

30

What length of WRS time signifies and incomplete or complete BBB?

normal - 0.11 s
incomplete - .10 - .12
complete - more than or equal to .12