Lab 1 - electrocardiography analysis Flashcards

1
Q

t/f the heart is the simplest organ

A

true

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2
Q

What is assessed by the electrocardiogram (ECG or EKG)

A

efficiency of the heart

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3
Q

area of the brain where sensory stimuli are monitored, information is relayed an adjustments are made according to the physical requirements of the body

A

medulla of the brain

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4
Q

the heart is a hollow organ made of muscular tissue called _____

A

myocardium

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5
Q

what is the first leg of the journey of blood in the heart in 6 steps

A
  1. CO2 saturated blood enters the right atrium from vena cave
  2. blood is pumped into right ventricle
  3. right ventricle pumps blood in pulmonary artery
  4. pulmonary artery carries blood to the lungs
  5. exchange of CO2 and O2
  6. carbon dioxide is exhaled
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6
Q

what is the second leg of the journey of blood in the body in 5 steps

A
  1. newly oxygenated blood goes back to left atrium via the pulmonary veins
  2. blood enters the left ventricle
  3. blood is forced out through the aorta
  4. blood goes to the tissues to deliver oxygen and nutrients (collects carbon dioxide)
  5. return to the heart - cycle begins again
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7
Q

serves as a reservoir from the ventricles, assuring a constant flow of blood through the heart

A

the atria

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8
Q

ventricular primer

A

atria

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9
Q

where are the specialized cells in the SA node located?

A

in the right atrium near the superior vena cava

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10
Q

what joins the myocardial cells tightly together

A

intercalated discs

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11
Q

what are intercalated dics?

A

lower resistance to electrical conductivity than the outside of the myocardium = quick propagation of the cardiac action potential

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12
Q

where is the AV node located?

A

roughly at the border between the atria and ventricles along the midline of the heart

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13
Q

From the AV node, the action potential travel downwards toward the apex of the heart via ____, and ____ and _____

A

Bundle of His, Right and left Bundle branches and Purkinje fibers

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14
Q

this electrical pathway is composed of ___ (explain)

A

specialized non-contractile, highly conductive cardiac tissue that ensures the heart depolarizes and contracts in a sequential manner and as a coordinated unit

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15
Q

The voltage changes caused by the action potentials can be measured on the body’s surface and are known the ____

A

electrocardiogram (ECG)

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16
Q

The usual amplitude of the voltage changes is only about __ mV but they can easily be recorded

A

1-2mV

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17
Q

Offers a reliable, non-invasive way of studying the integrity of the heart’s electrical conductive system and allows for an overall evaluation of cardiac health

A

Electrocardiogram (ECG)

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18
Q

three words to describe the heart’s electrical activity

A

polarisation, depolarisation, repolarisation

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19
Q

polarisation

A

refers to the heart at rest, awaiting a depolarising signal, normally from the SA node

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20
Q

depolarisation

A

discharge of electrical energy that triggers the contraction

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21
Q

repolarisation

A

electrical recovery of the heart as the cells recharge themselves and return to polarised state

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22
Q

which 2 phases from the heart’s electrical activity can be measured by the ECG

A

depolarisation and repolarisation

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23
Q

t/f the ECG trace is a measurement of the strength of the contractions of the heart

A

false

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24
Q

what is the ecg

A

recording of the electrical impulses prior to the contraction and relaxation of the myocardium

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25
Q

what are the letters of the ECG recording

A

P, Q, R, S, T and U

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26
Q

first waveform to appear

A

P wave

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27
Q

what occurs at the P wave

A

occurs as a result of the action potentials (depolarisation) that cause the atria to contract

28
Q

The P wave depicts (represents) what

A

atrial depolarisation

29
Q

waveform that represents the time required for the impulse to travel from the SA node to the AV node

A

P-R interval

30
Q

waveform that occurs as a result of ventricular depolarisation

A

QRS complex

31
Q

what does the termination of the QRS complex signify?

A

signify that all ventricular fibers have been depolarized and are now in a refractory period

32
Q

waveform represented by the S-T segment

A

refractory period

33
Q

Many ECGs show two negative deflection within the QRS complex - name them

A

Q and S waves

34
Q

t/f it is usual to see the Q or S wave absent

A

false

35
Q

waveform that represents the main phase of ventricular depolarisation and is always present under normal circumstances

A

R wave

36
Q

waveform that represents the repolarisation of the ventricles as the cells recharge themselves in preparation for another impulse coming down the heart’s intrinsic electrical conduction system

A

T wave

37
Q

waveform that represents the amount of time elapsed between the beginning of ventricular depolarisation and the completion of ventricular repolarisation

A

Q-T interval

38
Q

what is the supposed meaning of the U wave

A

may represent the repolarisation of the Purkinje fibers

39
Q

what is sinus arrhythmia

A

“accordion” effect on the ECG

irregular R wave

40
Q

t/f irregular R wave is always indicative of cardiac malfunction

A

false

41
Q

what is “being in sinus rhythm and beats”

A

when contractions of the heart are driven by the SA node

42
Q

Normal range of value for beats/min

A

60 to 100 beats/min

43
Q

Athletes trained in endurance events can have a normal heart rate as low as ___ bpm

A

55 bpm

44
Q

what HR is bradycardia

A

less than 60 bpm

45
Q

what HR is tachycardia

A

more than 100 bpm

46
Q

what is used to measure rate (ventricular depolarization)

A

rate of QRS complex or R wave peaks

47
Q

P wave consistency

A

Size, direction and position of the P wave in the ECG

48
Q

P-R interval duration

A

Measure the P-R intervals

Should be between 120msec and 200msec

49
Q

QRS complex duration

A

Value should not exceed or equal 120 msec

50
Q

t/f if any of the results of these 5 steps is abnormal, an arrhythmia can be postulated

A

true

51
Q

signs of hypertrophy - for atria

A

if the P wave amplitude is larger than 0.3 mV in either Leads 2,3, or AVF

52
Q

signs of hypertrophy - for left ventricle

A

if the R wave amplitude is larger than 1.4mV in Lead 1, or if the R wave amplitude is larger than 1.2mV in lead AVL

53
Q

signs of hypertrophy - right ventricle

A

if the R wave amplitude is larger than 0.5 mV in AVR

54
Q

t/f amplitudes smaller than the above listed cut-offs would indicate a normal heart rate

A

true

55
Q

what are the three things analyzed in our ECG analysis?

A

a) detecting arrhythmias
b) signs of hypertrophy
c) assess myocardial damage

56
Q

signs of myocardial damage - how to choose the wave analyzed?

A

largest upward waves - only one complex is analyzed

57
Q

Transient changes include ___ elevation or depression

A

S-T segment

58
Q

Persistent changes include ___ inversion and large ___

A

T wave, Q waves

59
Q

What is a heart block

A

it’s when the ventricles beat at their inherent rate (about 30 bpm) because there is a block in the normal conduction pathway

60
Q

Common place for heart block

A

AV node

61
Q

What is ectopic pacemakers

A

abnormal sites of spontaneous action potentials caused by localized area of damaged tissue that tend to produce extra action potentials = abnormal contractions

62
Q

Potentially the most serious type of arrhythmia

A

Fibrillation

63
Q

what is fibrillation

A

appears as random contractions and relaxations in the heart muscle = no useful pumping of blood by the heart

64
Q

where does fibrillation occurs

A

in the ventricles

65
Q

fibrillation is associated with

A

damaged myocardium due to poor blood supply resulting from a blockage of coronary arteries (ex: ischemia)

66
Q

t/f fibrillation in the atria is always life threatening

A

false, not necessarily

67
Q

solution to fibrillation

A

defibrillation = sending one big shock through the heart to make the cycle begin normally at the SA node