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Flashcards in Principles EKG 1 Deck (55):
1

What is monitoring?

Monitoring is making repeated or continuous observations or measurements of the patient, their physiologic function, and the function of life supporting equipment, for the purpose of guiding management decisions, including when to make therapeutic interventions and assessments of those interventions

2

What is electrocardiography?

Source of EMF in a 3-D space that is projected on planer surfaces

3

What three things do we look at on the ECG for anesthesia?

Rate
rhythm
ST segments

4

Where does the myocardial electrical activity start?

Initiates at the SA node

5

What does the SA node stand for and what does it mean?

Sinal atrial node
Means that the activity is sinus in rhythm

6

What is the electrically conductive tissue inside the body?

Volume conductors
Ie. Blood, pericardial fluid, interstitial fluid

7

How does air and other gases affect conductivity?

Air acts as a block in conductance

8

True or false: pores and capacitive coupling provide electrical access to the volume conductors from outside the body.

True

9

How are the half cell potentials that are produced between the skin and electrodes overcome?

By using amplifiers so that the half cell potentials are canceled out or blocked

10

Which amplifier is used so that the effects of the two half cell potentials are canceled out

Differential input DC amplifier

11

Which amplifier is used so that the DC voltage is blocked?

AC coupled amplifier

12

What type of amplifiers or most used in the OR today?

AC coupled differential amplifiers

13

Because of their stable half cell potential which electrodes are used in most medical applications

Silver-silver chloride (Ag-AgCl)

14

What is the most common mechanism that creates artifact signals?(That is signal's that could possibly obscured the real signal)

Electrode slippage

15

What is the most common type of electrode used today?

Column electrodes
These keep the electrode at a fixed distance from the skin

16

What is one of the original type of electrodes used that connects a metallic plate that is held to the skin by rubber strap

Plate electrodes

17

What is an original type of electrode that is similar to the plate electrodes but most often is used as a chest electrode

Suction cup electrodes

18

What was the main difference in the plate electrodes and the suction cup electrodes

The plate electrodes went on the extremities
The suction cup most often went to the patient's chest

19

EEG electrodes are much more sensitive than ECG electrodes because of what

Because the typical EEG electrodes are either a needle or a concave disk made of either gold or silver that is held by thick paste that is more conductive than what is used on the ECG

20

The "backpack" electrodes and the MRI electrodes have which side effect

They are not good for ST monitoring

21

What is the standard range of width of the clinical electrode used today

1 cm

22

The first electrometer used in 1887 by Agustus Waller used what

A 20 µ glass capillary tube filled with Mercury and was floating in sulfuric acid

23

What is a transmembrane action potential

A potential across a cell membrane where voltage is changing over time

24

Waller's pet bulldog was named what

Jimmie

25

True or False: Einthoven's Galvanometer required the patient to be hooked to electrodes and the hands and extremities to be placed in jars of salt solutions

True

26

Who in 1928 applied electronic amplification to the signal thus replacing the string galvanometer

Ernestine and Levine

27

Who in 1924 was credited with recognizing the vast potential importance of the ECG as a diagnostic and investigative tool

Einthoven

28

True or false, when depolarization occurs of a polarized cell, the cell becomes electronegative on the outside and positive on the inside, thus switching polarity

Tue

29

The magnitude of the electrical potential of a cell is given by what equation

The Nernst equation
EMF = -60ln {ion (out) / ion (in) }

30

What is the common baseline starting millivolts for most cells

-70 to -90

31

Look at the transmembrane potential on page 15

Or if someone can add it in I do not know how

32

At resting state what ions are in the cytoplasm and what ions are in the extracellular fluid

K is in the cytoplasm
Na is majority outside cell

33

What phase is depolarization of the cell

Phase 0

34

During phase 0 what is the movement of ions across the cell membrane

Na inside the cell

35

What is the net movement of ions across the cell membrane in phase 1

K out
Cl in

36

What is the net movement of ions across the cell membrane in phase 2

Calcium in
K out

37

What phase does repolarization take place

Phase 3

38

During phase 3, What is the net movement of ions across the cell membrane

K out

39

How many total phases are there in the transmembrane potential

4

40

What phase is most closely resemble to the resting state

Phase 4

41

True or false electrical activity always precedes mechanical activity in the heart

True is actually about 150 ms

42

All heart activity we measure should be what kind of action potential

A biphasic action potential

43

What theory states that the ECG is a result of temporal and spatial summation Of electrical activity of the heart as seen by electrodes placed external to the depolarizing cells of the myocardium

The interference theory

44

Some tissue repolarize in the opposite direction of the depolarization,what is the most notable tissue that this occurs in

Ventricular myocardium

45

What are leaky cells?
And where are the leaky cells?

Leaky cells are cells that do not maintain polarity and are also known as the pacemakers.
They are located in the SA node and the AV node

46

List the order of depolarization as it hits each of the myocardial cells

SA node
Atrial muscle
AV node
Common bundle
Bundle branches
Purkinje fiber
Ventricular muscle

47

What is known as the hoot owl theory

The dipole theory

48

What is the ECG measured in

mV

49

True or false: the farther away from the heart you go, the greater the voltage amplitude you will get

False

50

True or false electrical activity spreads across the heart via a defined anatomical pathway

True

51

What is another name for potential lines when the potential is the same everywhere on that line

Equipotential lines

52

True or false: current and potential lines exist in the limbs and extremities

False they do not exist in the limbs they only move in limbs through cable conduction

53

What are the surface potentials at any given moment in time in relation to the front and back

There is no symmetry from front to back in in surface potential

54

As far as myocardial electrical activity is concerned, vector length is equal to what

Length is the magnitude of the gradient
The higher the magnitude the longer the vector
The Lower the magnitude the shorter the vector

55

Vector direction indicates what

The anatomical pathway of the electrical activity