Brainscape's Knowledge GenomeTM

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


See full index

IBHRE® > Fundamentals of electrophysiology > Flashcards

Fundamentals of electrophysiology Flashcards

Arms the student with basic E.P. and electrical concepts. All pacemaker theory is built upon the understanding of these principles. Currently weighted 3% in the CCDS exam.

1
Q

Define ‘Automaticity’.

A

The cells ability to spontaneously depolarise or the ability to initiate an impulse.

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

What is the resting membrane potential of a P-cell?

A

-50 to -60mV.

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

Is progression of SND to CHB considered likely or unlikely?

A

Unlikely.

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

Sarcoidosis / Giant cell myocarditis accounts for what % of unexplained AV block in <55yr old pts?

A

25%.

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

Which type of 2nd degree AVB is most likely to progress to CHB?

A

2nd Degree Mobitz II.

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

List 4 examples of reversible AV block.

A
  1. Lyme Carditis disease
  2. Drug toxicity
  3. Vagotonia
  4. Hypoxia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the strongest predictor of whether bifascicular block will advance to CHB?

A

Symptoms are the strongest predictor of disease progression.

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

Will pacing for bifascicular block improve mortality?

A

No.

It only improves symptoms.

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

Define ‘Resting Membrane Potential’.

A

Intracellular charge is more negative than extracellular charge.

Due to the cell membrane being more permeable to both K and NA+.

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

Define cellular ‘Depolarisation’.

A

Intracellular charge becomes less negative than extracellular charge due to the exchange of ions across the cell membrane.

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

Define ‘Repolarisation’.

A

Intracellular charge to return to a more negative state than extracellular charge due to re-exchange of ions across the cell membrane.

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

Phase 0 is otherwise known as?

A

Rapid Depolarisation.

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

Phase 1 is otherwise known as?

A

Early Repolarisation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Phase 2 is otherwise known as?

A

Plateau Phase.

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

Phase 3 is otherwise known as?

A

Rapid Repolarisation.

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

Phase 4 is otherwise known as?

A

Resting Phase.

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

During Phase 0 (Rapid Depolarisation), which ions flow into the cell and how quickly?

A

Sodium moves rapidly in.

Calcium moves slowly in.

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

During Phase 1 (Early Repolarisation), which ions flow in/out of the cell?

A

Sodium channels close - Membrane is impermeable to sodium.

Calcium moves slowly in.

Activation of transient outward potassium current (Ito)

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

During Phase 2 (Plateau Phase), which ions flow in/out of the cell?

A

Calcium moves slowly in.

Potassium moves slowly out.

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

During Phase 3 (Rapid Repolarisation), which ions flow in/out of the cell?

A

Calcium channels close - Membrane is impermeable to calcium (& sodium still).

Potassium moves rapidly out.

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

During Phase 4 (Resting Phase), which ions flow in/out of the cell?

A

Active transport pumps Potassium in.

Active transport pumps Sodium out.

Membrane still impermeable to both Calcium & Sodium.

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

What phase of the cardiac cycle is responsible for myocardial contraction?

A

Phase 0.

The cellular charge changing from negative to positive triggers contraction.

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

When combined, which phases equate to the Absolute Refractory Period?

A

Phases 0, 1, 2 and early phase 3.

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

When combined, which phases equate to the Relative Refractory Period?

A

Late phase 3 and phase 4.

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

The following statement best defines which refractory period?

‘The cell cannot accept a stimulus no matter the strength’.

A

Absolute Refractory Period (AKA Effective Refractory Period).

The cell cannot accept a stimulus due to cellular supersaturation of ions.

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

The following statement best defines which refractory period?

‘The cell can be stimulated but requires a greater than normal stimulation strength’

A

Relative Refractory Period.

This is due to cellular saturation of ions returning to baseline but isnt yet at true baseline.

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

Define ‘Excitablity’.

A

Threshold at which a cell will respond to a stimulus / Cells ability to respond to an impulse.

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

Define ‘Conductivity’.

A

How well the cell passes on a stimulus / Cells ability to transmit an impulse.

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

Under normal resting conditions, what is the automatic firing rate of the SA Node?

A

60-100bpm.

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

Below what heart rate is considered Sinus Bradycardia?

A

<60bpm.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Above what heart rate is considered Sinus Tachycardia?

A

>100bpm.

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

How many internodal tracts are there in the Right Atrium?

A

x3 (Anterior, Middle, Posterior).

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

Define the purpose of the Bachmanns Bundle.

A

To provide rapid impulse conduction to the Left Atrium.

This facilitates synchronous contraction of both the left and right Atria.

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

Define where the AV Node is located.

A

Inferior Right Atrium near osmium of Coronary Sinus.

Apex of Triangle of KOCH.

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

What does the AV Node do to the impulse it receives from the Atria and why?

A

Delays the signal for approximately 120 msec.

This allows for ventricular filling respondent to atrial contraction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the secondary purpose of the AV Node with regards to rate control?

A

AVN has decremental conduction properties, which prevents rapid impulses originating in the atria from reaching the ventricles.

E.g. 250bpm Atrial-Flutter conducted 1:1 would prevent adequate ventricular filling. AVN blocks these impulses in a typically 2:1 or 3:1 fashion, which facilitates stable haemodynamics.

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

What electrical anatomical structure follows the AV Node?

A

The bundle of HIS follows the AV Node.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is the automatic firing rate of the bundle of HIS.

A

40-60 bpm.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

True / False

The left bundle branch divides into two arms vs. the right bundle branch’s one arm.

A

True.

The left has both the Anterior and Posterior Fascicle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

True / False

Left bundle branch conduction velocity exceeds that of the right bundle branch.

A

True.

In order to deploarise the greater amount of tissue comprising the left ventricle, while maintaining synchronousity to the smaller right ventricle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is the final structure of the electrical conduction system.

A

Purkinje Fibres.

Responsible for innervating deep into the ventricular wall.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is the automatic firing rate of the Purkinje Fibres?

A

15-40bpm.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is the most likely type of arrhythmia described below.

‘Re-entry circuits within the atrium, AVN excluded, fires between 150-250bpm’.

A

Atrial Flutter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What structure within the Right Atrium precipitates the majority of Atrial Tachycardias?

A

Crista Terminalis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Describe the Crista Terminalis structure.

A

Endocardial ridge that divides smooth atrial tissue and the trabeculated appendage.

The meeting of different tissues with differing conduction properties forms the substrate for the majority of tachycaridas.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Increase / Decrease

Predominant sympathetic SA node innervation will result in which HR response?

A

Increased Heart Rate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Increase / Decrease

Predominant parasympathetic SA node innervation will result in which HR response?

A

Decreased Heart Rate.

48
Q

What is the most common type of SVT treated today?

A

Atrio-Ventricular-Nodal-Re-entrant-Tachycardia (AVNRT).

49
Q

What is the most likely type of arrhythmia described below?

‘Re-entrant circuit of two anatomically & physiologically separate pathways confined to the AV node’.

A

AVNRT.

50
Q

Structurally, what is the major way AVNRT differs from AVRT?

A

AVNRT is a micro re-entry pathway encased within the AV Node.

AVRT involves accessory pathways located outside the AV node and is known as a macro circuit.

51
Q

In the context of AVNRT, which pathway is described below?

‘Has a relatively short Absolute Refractory Period and conducts slowly’.

A

The slow pathway.

52
Q

In the context of AVNRT, which pathway is described below?

‘Has a relatively long Absolute Refractory Period and conducts quickly’

A

The fast pathway.

53
Q

For AVNRT to propagate, a person is said to have what type of nodal physiology?

A

Dual Nodal Physiology.

i.e. Both a Fast and Slow Pathway are present and functional.

54
Q

What is the typical route for AVNRT?

A

Antegrade down the slow pathway. Retrograde up the fast pathway.

55
Q

What is the atypical route for AVNRT?

A

Antegrade down the fast pathway. Retrograde up the slow pathway.

56
Q

True / False

No P-wave is visible during typical AVNRT due to simultaneous firing of the Atria and Ventricles.

A

True.

P-wave is usually buried in the QRS complex and thus invisible on a surface ECG.

57
Q

True / False

No P-wave is visible during atypical AVNRT due to simultaneous firing of the Atria and Ventricles.

A

False

P-wave is usually visible in the T-wave.

58
Q

Delta-waves on an ECG are typically indicative of what congenital condition?

A

Wolff-Parkinson-White Syndrome (WPW).

59
Q

What structures must be present to facilitate AVRT.

A

Accessory Pathways.

60
Q

True / False

If an Accessory Pathway conducts retrograde only, a delta wave will be observable on the ECG.

A

False.

Any electrical activation will be buried by the QRS complex. Only Antegrade AP conduction will show delta waves.

61
Q

If an Accessory Pathway conducts retrogradely only, it is said to be what type of pathway?

A

Concealed.

As there are no ECG markers visible. They are ‘concealed’ by the QRS complex.

62
Q

True / False

Pre-excitation highlights early activation of the ventricular myocardium respondent to conduction through an accessory pathway ahead normal conduction through the AV Node.

A

True.

A slurred upstroke on the QRS shows early activation in the region of the AP. As conduction through the AV Node occurs, the QRS ‘catches up’ as the remainder of the ventricular myocardium depolarises.

63
Q

What are 3 common ECG hallmarks of Wolff Parkinson White.

A
  1. Short PR Interval (<120ms)
  2. Broad QRS due to delta wave (>120ms)
  3. Abnormal T-waves
64
Q

Yes / No

Can delta waves be seen during Orthodromic AVRT?

A

No.

The impulse is travelling antegrade through the AV Node and retrograde up the AP. Thus any ECG signals are concealed by the QRS.

65
Q

Yes / No

Can delta waves be seen during Antidromic AVRT?

A

Yes.

The impulse is travelling retrograde up through the AV Node and antegrade down the AP. Thus pre-excitation of the QRS will be seen.

66
Q

Is Orthodromic AVRT considered Typical or Atypical?

A

Typical.

It’s the most common type.

67
Q

Is Antidromic AVRT considered Typical or Atypical?

A

Atypical.

It’s the less common type.

68
Q

What arrhythmia is best described below?

‘Atrial Rhythm is regular at a rate of 250-350bpm’.

A

Atrial Flutter.

69
Q

True / False

Atrial Flutter is a Micro re-entrant circuit contained predominantly within the left atrium.

A

False.

It is a Macro re-entrant circuit most commonly contained within the right atrium.

70
Q

True / False

Typical Flutter gives rise to a sawtooth baseline pattern on an ECG.

A

True.

71
Q

True / False

Atypical Flutter is commonly negative in inferior leads II, III, and AVF.

A

False

Typical Flutter will commonly be negative in the inferior leads II, III, and AVF.

72
Q

Typical / Atypical

The following statement best describes which flutter type?
‘Substrate is an anatomically distinct area of delayed conduction located between the IVC, CSos and and Tricuspid Valve Annulus’.

A

Typical Flutter.

Atypical Flutter commonly forms around other areas of block to conduction.

73
Q

Which ECG leads are best for observing a sawtooth baseline respondent to flutter?

A

Typically V1 or Inferior leads II, III, and AVF.

74
Q

Which is commonly faster: Typical or Atypical Flutter?

A

Atypical Flutter is generally faster than Typical.

75
Q

What arrhythmia is best described by the following statement?

‘Irregular firing of the Atria and resultantly irregular contraction of the Ventricles’.

A

Atrial Fibrillation (with intrinsic conduction).

76
Q

What arrhythmia is best described by the following statement?

‘Impulse originates in the Ventricles and regularly fires between 100-200bpm’.

A

Ventricular Tachycardia.

77
Q

List the 3 categories associated with structural based VT.

A
  1. Automatic
  2. Re-entrant
  3. Triggered
78
Q

List the 2 categories associated with idiopathic non-structural VT.

A
  1. RVOT (most common)
  2. Fascicular VT

10% of all VT occurs in pts. with no apparent structural heart disease

79
Q

True / False

Automatic based VT is most commonly associated with myocardial scarring.

A

False.

Automatic VT = Acute metabolic crisis (Dialysis) or post MI reperfusion.

Re-entry VT = Myocardial Scarring.

80
Q

True / False

Re-entrant VT is most commonly associated with myocardial scarring.

A

True.

Scarring post MI is the most common substrate for re-entrant VT.

81
Q

Automatic / Triggered

Which VT type is described best by the following statement?

‘VT caused by leakage of IONS during the action potential and occurs spontaneously’.

A

Automatic.

Triggered is also caused by leakage of IONS during AP, however rarely occurs spontaneously. It almost always requires a premature impulse.

82
Q

Automatic / Triggered

Which is described best by the following statement.

‘VT caused by leakage of IONS during the action potential and occurs following a premature beat’.

A

Triggered.

Automatic is also caused by leakage of IONS during AP, however doesn’t require a premature impulse. It almost always occurs spontaneously.

83
Q

What arrhythmia is best described by the following statement?

‘Chaotic irregular impulses that originate in the Ventricles’.

A

Ventricular fibrillation.

84
Q

The statement below best defines what quantity?

‘Unit of electric current (flow of 1 coulomb per sec)’.

A

The Ampere.

85
Q

The statement below best defines what quantity?

‘Unit of electric charge’.

A

The Coulomb.

86
Q

The statement below best defines what quantity?

‘Unit of electric resistance’.

A

The Ohm.

87
Q

The statement below best defines what quantity?

‘Unit of electric potential and electromotive force’.

A

The Volt.

88
Q

The statement below best defines what quantity?

‘Unit of frequency’.

A

The Hertz.

89
Q

The statement below best defines what quantity?

‘Unit of capacitance’ (Ability of body to store charge).

A

The Farad.

90
Q

The statement below best defines what quantity?

‘Unit of Energy’.

A

The Joule (1J per second = 1 Watt)’.

91
Q

V = I x R describes what law?

A

OHMS Law.

V = Power in Voltage / I = Current in Amperes / R = Impedance in Ohms.

92
Q

E = V x I x T describes what?

A

The Energy Equation.

E = Energy in Joules / V = Power in Voltage / I = Current in Amperes / T = Time in seconds.

93
Q

True / False

E = V x I x T can also be written E = V x Q.

A

True.

Charge (Coulomb) = Current (Ampere) x Time Thus I x T = Q.

94
Q

What is the equation used to calculate battery longevity?

A

(114 x Battery capacity in Ampere hrs) / Current drain in micro Amperes (uA).

95
Q

What is the formula required in order to calculate energy usage of a device?

A

(Voltage squared / resistance) x pulse width.

96
Q

True / False

Doubling the output voltage equates to a four fold increase in energy drain.

A

True.

Hence setting a lower voltage and higher pulse width is almost always desirable.

97
Q

True / False

Doubling the output pulse width equates to a four fold increase in energy drain.

A

False.

Doubling the pulse width only doubles the energy drain. Hence setting a lower voltage and higher pulse width is almost always desirable.

98
Q

With respect to electronics, what does the following symbol pertain to?

‘A’

A

The Ampere.

The unit of electrical current.

99
Q

With respect to electronics, what does the following symbol pertain to?

‘C’

A

The Coulomb.

The unit of electrical current.

100
Q

With respect to electronics, what does the following symbol pertain to?

‘Ω’

A

The Ohm.

The unit of electrical resistance.

101
Q

With respect to electronics, what does the following symbol pertain to?

‘V’

A

The Volt.

The unit of electrical potential.

102
Q

With respect to electronics, what does the following symbol pertain to?

‘Hz’

A

The Hertz.

The unit of Frequency.

103
Q

With respect to electronics, what does the following symbol pertain to?

‘F’

A

The Farad.

The unit of electrical capacitance.

104
Q

What is the resting membrane potential of a Cardiomyocyte?

A

-90mV.

Remember a P-cell is -50 to 60mV.

105
Q

Which of the 5 Phases of Action Potential is considered ‘Repolarisation’?

A

Phase 3.

Outward flow of Ions exceed inward flow of Ions.

106
Q

True / False

Cells capable of spontaneous automaticity exhibit gradual upward drift in transmembrane potential until threshold is reached.

A

True.

Examples of such cells are SA and AV Nodal Cells.

107
Q

True / False

The resting voltage of P-Cells is more negative than that of Cardiomyocytes.

A

False.

P-Cell = -50 to -60mV / Cardiomyocyte = -90mV.

108
Q

Why is the resting voltage of Cardiomyocytes is more negative than that of P-Cells?

A

P-Cells posses fewer inward rectifier K+ channels than cardiomyocytes.

More channels = larger voltage drop.

109
Q

True / False

During Phase 0, Sodium (NA+) flows rapidly out of the cell.

A

False.

During Phase 0 Sodium Flows inwards.

110
Q

True / False

During Phase 2, Calcium (Ca) flows rapidly into the cell.

A

True.

111
Q

Which of the 5 Phases of Action Potential is considered the start of ‘Diastolic Depolarisation’?

A

Phase 4.

112
Q

True / False

In a circuit, electrons always leave via the Anode.

A

True.

Anode = Away.

113
Q

True / False

In a circuit, electrons always enter via the Cathode.

A

True.

Cathode = Come towards.

114
Q

The rapid upstroke of the purkinje fiber AP (phase 0) is related to which of the following currents?

  1. ICa
  2. IKr
  3. IKs
  4. INa
A

4 - INa

Rapid influx of sodium ions.

115
Q

What is the current that flows to the myocardium for the following?

‘Output is 2.5V and lead resistance is 565 Ohms’

A

V = IR thus I = V/R

2.5V / .565Kohm = 4.4mA

Remember ohms must be changed to Kohms to give answer in mA.

116
Q

If one halves the output of a generator from 2V to 1V - the energy delivered is what?

  1. Halved
  2. Quadrupled
  3. Doubled
  4. Quartered
A

4 - Quartered.

E = (V2/R)*T

IBHRE® (24 decks)

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