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Clinical Methods Final > EKG basics > Flashcards

Flashcards in EKG basics Deck (28):
1

what is true of myocytes

polarized at rest
inside is negatively charged compared to out
membrane pumps (control ion distribution) necessary to keep inside electronegative

2

what is needed to keep cell polarized (in this state)

ATP

3

Na K pump moves how many ions?

3 Na out
2 K in

4

how do cardiac cells lose their internal negativity?

depolarization

5

how many types of cells in the heart?

1. pacemaker cells - power
2. electrical conducting cells - wiring
3. myocardial cells - contraction

6

what is true of pacemaker cells

innate electrical characteristics
input from nerual and hormonal
serve as a source of a wave of depolarization

7

what are the phases of action potential

phase 0 - rapid Na influx
phase 1 - K & Cl efflux
phase 2 - Ca influx K efflux
phase 3 - K efflux
phase 4 - K influx

8

what is automaticity?

all heart cells possess ability to behave as a pacemaker. Suppressed unless SA node fails

9

What is rate of of sites?

sa - 60-100 / min
av - 40 - 60
bundle 30 - 40
perk. 30 - 40

10

what is excitation- contraction coupling?

Actin and Myosin and when a wave of depolarization reaches a myocardial cell, calcium is released within the cell, causing the cell to contract.

11

True or false: Myocardial cells CAN transmit electrical current like conducting cells

true

12

what is time and length of small squares?

1 mm
0.04 s

13

what is time and length of big squares?

5 mm
0.2 s

14

verticle axis = voltage

small square - 0.1 mV
big square - 0.5 mV

15

what does PR interval represent?

start of atrial depolarization to start of ventricular depolarization.

16

What does ST segment represent?

Measures time from the end of ventricular depolarization to the start of ventricular repolarization

17

What does QT segment represent?

Measures time from beginning of ventricular depolarization to the end of ventricular repolarization.

18

how does a biphasic wave come about?

depolarizing wave moving perpendicular to a positve electrode

19

12 lead ECG consists of what types of leads?

6 limb (3 standard 3 augmented)
6 precordial

20

what are the signs on lead 1

right arm ( – ) left arm( +)

21

what are the signs on lead 2

right arm ( –) legs( +)

22

what are the signs on lead 3

left arm (–) legs( +)

23

what is true of precordial leads?

illustrate horizontal plane
all electrodes are (+) with (-) central terminal

24

what are positions for precordial electrodes?

V1 – 4th intercostal space to right of sternum
V2 – 4th intercostal space to left of sternum
V3 – between V2 and V4
V4 – 5th intercostal space in midclavicular line
V5 – 5th intercostal space at anterior axillary line
V6 – 5th intercostal space in midaxillary line

25

Which leads allow you to see anterior view

V1, V2, V3, V4

26

Which leads allow you to see left lateral view

I, AVL, V5, V6

27

Which leads allow you to see inferior view

II, III, AVF

28

Which lead is not used ?

AVR