Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

physiology lab exam > lab 10 electrocardiography and cardiovascular sounds II > Flashcards

lab 10 electrocardiography and cardiovascular sounds II Flashcards

1
Q

who introduced electrocardiography?

A

Willem Einthoven

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the QRS complex?

A

it is associated with the excitation of the ventricular muscle mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the first point of myocardial excitation?

A

left ventricle at the apex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the first vector?

A

septal activation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how long does septal activation take?

A

0.01 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the characteristics of septal activation?

A

the septal vector is oriented from the left ventricle to the right ventricle because the left ventricular component starts earlier and involves a larger segment of myocardium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the second vector?

A

free wall activation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how long does free wall activation take?

A

0.015-0.025 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the characteristics of free wall activation?

A

the free-wall vector is oriented from the left ventricular endocardium toward the left ventricular epicardium. although a similar activation occurs in the free wall of the right ventricle, the involvement of the larger muscle mass of the left ventricle results in the net force as described; the laterally directed components are approximately equal and opposite, thus they cancel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the third vector?

A

basal activation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how long does basal activation take?

A

0.005-0.01 sec

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the characteristics of basal activation?

A

the base of the ventricle is activated by a vector moving in an apicobasilar direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

to explain the vector’s impact at surface electrodes, what must one consider?

A
  1. the orientation of the three vectors with respect to the surface electrodes’ lead axis
  2. the general determinants of the distantly recorded potentials in a volume conductor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the 3 planes? (XYZ)?

A

X: sinistrodextral, Y: craniocaudal. Z: dorsoventral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is an orthogonal lead system?

A

a system that uses electrode positions so the lead axis is equivalent to one of the geometrical axes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is an example of an orthogonal lead system?

A

V10, aVF, lead I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is v10?

A

it is a unipolar lead with the positive electrode located over the 7th thoracic spinous process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what axis is the V10 equivalent to?

A

the Z (dorsoventral axis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is aVF?

A

the positive electrode is on the left hindlimb and the reference electrode is the combined right and left thoracic limbs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what axis is aVF equivalent to?

A

Y axis (craniocaudal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is is lead I?

A

it has the positive electrode on the left thoracic limb and the negative electrode on right thoracic limb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the lead I equivalent to?

A

the Z axis (sinistrodextral)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

when is a positive deflection elicited?

A

when the wave of depolarization moves toward the positive electrode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

when is a negative deflection recorded?

A

when the orientation is reversed so the depolarization moves toward the reference electrode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

when does no deflection occur?

A

when the uncancelled vector is oriented at right angles to the lead axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what is the recorded potential proportional to?

A

the magnitude of the net electrical vector and the proximity of the electrode to it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

how can the relationship of the recording to the depolarization be summarized?

A

recorded potential=source potential/distance from source to recording electrode *cos (angle that vector makes with lead axis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what species have a similar QRS to the dog?

A

dog, man, monkey, rat, cat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what species have a dissimilar QRS compared to the dog?

A

horse, goat pig, sheep, cow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what is the series of depolarizations in the horse, goat, pig, sheep, cow?

A
  1. initial depolarization of the subendocardial shell surrounding the apex of the left ventricle
  2. terminal depolarization of the middle and basilar thirds of the interventricular septum in an apico-basilar direction
  3. generalized depolarization of ventricular muscle mass without creation of a wave of depolarization
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what is the main concept of measuring the mean electrical axis of the heart?

A

that you can consider the ventricular excitation as being represented by a single electrical vector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is einthoven’s law?

A

lead I-lead II+ lead III=0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what is the main utility of Einthoven’s law?

A

to ascribe an angular orientation to the mean electrical axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

how many leads are required to plot the mean electrical axis?

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what are the three basic methods for estimating the mean electrical axis using the three standard limb leads and three augmented leads?

A
  1. measure the algebraic sum of the QRS deflections in leads I, II and III and plot on a triaxial system
  2. find an isoelectric lead, the algebraic sum of the QRS deflections being zero
  3. choose the lead with the largest net QRS deflection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what is the normal range of the mean electrical axis in the dog?

A

40-100 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

if the mean electrical axis of the dog is greater than 100 degrees, what is this called?

A

right angle deviation

38
Q

what is right angle deviation associated with?

A

right ventricular hypertrophy

39
Q

by convension, a one centimeter deflection represents a potential of how much?

A

1 mV

40
Q

what is the normal paper speed for small animals?

A

50mm/sec

41
Q

what is the normal paper speed for large animals

A

25mm/sec

42
Q

what are bipolar leads?

A

when both electrodes are sufficiently close to the heart to be influenced by it, this is called a bipolar lead system

43
Q

what is lead I?

A

the potential difference is recorded between the left(+) and right forelimbs

44
Q

what is lead II?

A

the potential difference is recorded between the left hindlimb (+) and right forelimb

45
Q

what is lead III

A

the potential differnce is recorded between the left hindlimb (+) and the left forelimb

46
Q

what are unipolar leads

A

unipolar leads (unaugmented) measure potentials betwen an exploring electrode in proximity to the potential source versus a distant reference electrode or versus a neutralizing reference

47
Q

what are augmented unipolar limb leads?

A

they utilize the standard electrode placements with one electrode serving as the exploring electrode and the remaining two combined as the reference

48
Q

what aVR

A

it is the right forelimb considered as positive with the other two as reference

49
Q

what is aVL?

A

it is the left forelimb considered as positive with the other two as references

50
Q

what is aVF

A

it is the left hindlimb considered as positive with the other two as references

51
Q

what are precordial unipolar leads?

A

it is a unipolar lead with the reference as the central terminal of wilson where the limb electrodes are connected through 5000 ohm resistors to a single point which serves as a reference or electrical zero

52
Q

how do you measure the mean electrical axis?

A

the positive and negative deflections in lead I and lead III are added. the perpendicular lines are then followed from the positive or negative point determined for each lead in the triaxial system. A line drawn from the triaxial system to the point of the intersected perpendicular lines gives the direction and relative magnitude of the mean QRS vector

53
Q

what is the P-R interval?

A

the interval from the BEGINNING of the P wave to the BEGINNING of the QRS complex. it corresponds to the time taken for the excitation to spread from the SA node the beginning of the spread through the ventricular musculature

54
Q

what is the P-R segment?

A

it is an isoelectric point measured from the END of the P wave to the BEGINNING of the first deflection away from baseline of the QRS complex

55
Q

what is the QRS complex?

A

the Q wave is the first negative defleciton, the R wave is the first positive deflection. the S wave is a negative deflection occurring after a negative and//or positive R deflection
the length of the QRS measures the time for ventricular depolarization

56
Q

what is the Q-T interval

A

it is the interval from the BEGINNING of the QRS to the END of the T wave and measures ventricular depolarization and ventricular repolarization. it approximates ventricular contraction

57
Q

what is the S-T segment?

A

it is the period from the END of the QRS complex to the BEGINNING of the T wave. it corresponds to the plateau period of the ventricular myocardial action potential and is normally isoelectric or only slightly displaced from it.

58
Q

what is percussion?

A

the elicitation of sounds from parts of the body by tapping with fingers or an instrument.

59
Q

what is auscultation

A

the detection and study of sounds produced in the body

60
Q

what causes sounds?

A

they result from a vibrating body causing vibrations or waves in the air, which, when impinging upon the ear, are perceived as sound.

61
Q

what are tones?

A

sounds produced by regular oscillations causing a series of waves vibrating at a uniform rate

62
Q

what does intensity depend upon?

A

the amplitude of vibration

63
Q

what does pitch depend on?

A

the number of vibrations produced in a given period of time (frequency)

64
Q

what are transients?

A

cardiovascular sounds of short duration

65
Q

what are murmers

A

cardiovascular sounds of longer duration

66
Q

what is a phonocardiogram?

A

the recording of the sounds from the heart

67
Q

what is the first heart sound?

A

it occurs at the termination of atrial contraction and onset of ventricular contraction (closing of AV valves)

68
Q

what is the second heart sound?

A

it is the closing of the semilunar valves

69
Q

what is splitting

A

when the heart sound is split; it is more likely to occur with the second heart sound and during inspiration (the pulmonary lags the aortic) b/c increased negative thoracic pressure draws blood back to right ventricle and prolongs ejection phase

70
Q

what is the third heart sound?

A

it is the sound occuring during diastole and is generally due to rapid inflow of blood, usually occurs during end of rapid filling phase when ventricle walls are less flaccid (more taut)

71
Q

what is the fourth heart sound?

A

it is the sound produced by atrial systole

72
Q

which sound is more intense in the dog and man?

A

the first sound

73
Q

which sound is often more intense in the horse?

A

the second heart sound

74
Q

is splitting common in healthy dogs?

A

no

75
Q

is splitting of the second sound common in horses?

A

yes

76
Q

what are examples of abnormal sounds?

A

ejection sounds
systolic clicks
gallop rhythms

77
Q

what are ejection sounds?

A

sharp high pitched sounds that occur shortly after first heart sound when aortic and pulmonary valves open and is considered due to forceful ejection of blood into dilated great vessels

78
Q

what are systolic clicks?

A

extra sounds that sound like clicking between first and second heart sound

79
Q

what are gallop rhythms?

A

due to occurrence of first, second and another heart sound

80
Q

what are murmurs?

A

cardiovascular sounds of longer duration
due to turbulent flow due to obstructions in path of blood flow
timing, intensity, pitch over each four valve regions should be noted

81
Q

when is a stenosis of an AV valve heard?

A

in diastole

82
Q

when is a stenosis of a semilunar valve heard?

A

in systole

83
Q

when is an insufficiency in an AV valve heard generally

A

in systole

84
Q

when is an insufficiency in a semilunar valve heard generally

A

in diastole

85
Q

what is the characteristic of an AV valve stenosis?

A

decrescendo diastolic with a presystolic accentuation if atrium contracts; low pitched, rumbling, rare

86
Q

what is the characteristics of an AV valve insufficiency?

A

pansystolic, medium pitched, common

87
Q

what are characteristics of a semilunar valve stenosis

A

diamond shaped holosystolic; medium pitched, may be harsh; associated with heart worms; rare

88
Q

what are the characteristics of semilunar valve insufficiency?

A

decrescedo diastolic; high pitched; uncommon

89
Q

what are common non-valvular murmurs?

A

anemia
ventricular septal defect
patent ductus arteriosus (with left to right sjunt)

90
Q

when is a murmur due to anemia heard?

A

during early systole;

91
Q

when is a murmur associated with a ventricular septal defect heard?

A

during systole; varies in pitch; rough

92
Q

when is a continuous murmur of patent ductus arteriosus heard?

A

the whole time

physiology lab exam (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions