Principles EKG 1

Question 1

What is monitoring?

Answer 1

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

Question 2

What is electrocardiography?

Answer 2

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

Question 3

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

Answer 3

Rate
rhythm
ST segments

Question 4

Where does the myocardial electrical activity start?

Answer 4

Initiates at the SA node

Question 5

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

Answer 5

Sinal atrial node

Means that the activity is sinus in rhythm

Question 6

What is the electrically conductive tissue inside the body?

Answer 6

Volume conductors

Ie. Blood, pericardial fluid, interstitial fluid

Question 7

How does air and other gases affect conductivity?

Answer 7

Air acts as a block in conductance

Question 8

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

Answer 8

True

Question 9

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

Answer 9

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

Question 10

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

Answer 10

Differential input DC amplifier

Question 11

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

Answer 11

AC coupled amplifier

Question 12

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

Answer 12

AC coupled differential amplifiers

Question 13

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

Answer 13

Silver-silver chloride (Ag-AgCl)

Question 14

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

Answer 14

Electrode slippage

Question 15

What is the most common type of electrode used today?

Answer 15

Column electrodes

These keep the electrode at a fixed distance from the skin

Question 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

Answer 16

Plate electrodes

Question 17

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

Answer 17

Suction cup electrodes

Question 18

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

Answer 18

The plate electrodes went on the extremities

The suction cup most often went to the patient’s chest

Question 19

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

Answer 19

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

Question 20

The “backpack” electrodes and the MRI electrodes have which side effect

Answer 20

They are not good for ST monitoring

Question 21

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

Answer 21

1 cm

Question 22

The first electrometer used in 1887 by Agustus Waller used what

Answer 22

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

Question 23

What is a transmembrane action potential

Answer 23

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

Question 24

Waller’s pet bulldog was named what

Answer 24

Jimmie

Question 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

Answer 25

True

Question 26

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

Answer 26

Ernestine and Levine

Question 27

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

Answer 27

Einthoven

Question 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

Answer 28

Tue

Question 29

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

Answer 29

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

Question 30

What is the common baseline starting millivolts for most cells

Answer 30

-70 to -90

Question 31

Look at the transmembrane potential on page 15

Answer 31

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

Question 32

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

Answer 32

K is in the cytoplasm | Na is majority outside cell

Question 33

What phase is depolarization of the cell

Answer 33

Phase 0

Question 34

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

Answer 34

Na inside the cell

Question 35

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

Answer 35

K out | Cl in

Question 36

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

Answer 36

Calcium in | K out

Question 37

What phase does repolarization take place

Answer 37

Phase 3

Question 38

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

Answer 38

K out

Question 39

How many total phases are there in the transmembrane potential

Answer 39

4

Question 40

What phase is most closely resemble to the resting state

Answer 40

Phase 4

Question 41

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

Answer 41

True is actually about 150 ms

Question 42

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

Answer 42

A biphasic action potential

Question 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

Answer 43

The interference theory

Question 44

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

Answer 44

Ventricular myocardium

Question 45

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

Answer 45

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

Question 46

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

Answer 46

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

Question 47

What is known as the hoot owl theory

Answer 47

The dipole theory

Question 48

What is the ECG measured in

Answer 48

mV

Question 49

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

Answer 49

False

Question 50

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

Answer 50

True

Question 51

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

Answer 51

Equipotential lines

Question 52

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

Answer 52

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

Question 53

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

Answer 53

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

Question 54

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

Answer 54

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

Question 55

Vector direction indicates what

Answer 55

The anatomical pathway of the electrical activity