Rhythm of the heart Flashcards

1
Q

Major ions in cardiac myocytes:

A

Ca2+
Na_
K+

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2
Q

Phase 4 of AP cardiac myocyte:

A

RMP - K+ is moving out of the cell.

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3
Q

What causes the rapid depolarisation

A

Opening of fast voltage Na+ channels

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4
Q

What causes plataeu phase?

A

K+ and voltage gated Ca2+ open

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5
Q

How do pacemaker potentials differ?

A

Slow Ca2+ and Na+ influx. Then L-type Ca2+ open to rapidly let Ca2+ in.

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6
Q

Intrinsic rate of SAN

A

60-100 bpm

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7
Q

Bachmann’s bundle =

A

SAN to atria

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8
Q

What spreads electrical impulse rapidly and synchronously though LV and RV

A

His-Purkinje system

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9
Q

What happens when PNS increases?

A

Slows HR

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10
Q

When does PNS increase?

A

Sleep
Vasovagal syncope
fittness

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11
Q

When does PSN decrease?

A

First seconds of exercise
Heart failure
Atropine

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12
Q

First seconds of exercise vs after

A

First seconds = PSN decrease

After = SNS increases

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13
Q

When does SNS increase?

A

After first min of exercise
Fear
Adrenaline
Salbutamol

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14
Q

When does SNS decrease?

A

Rest and sleep
Beta blockers
Vasovagal syncope

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15
Q

P wave =

A

depolarisation of atria

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16
Q

QRS =

A

depolarisation of venticles

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17
Q

PR intervals =

A

Conduction through AV node

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18
Q

PR segment =

A

time taken to get signal from SAN and AVN

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19
Q

Q is depolarisation of

A

Interventricular septum

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20
Q

R is depolarisaiton of

A

Mass of ventricles

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21
Q

S is depolarisation of

A

Apex

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22
Q

QT interval =

A

Reflects repolarisation of ventricular myocardium

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23
Q

Normal PR interval is

A

<200 m sec

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24
Q

< 200msec is equivalent to

A

<5 small squares

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25
Q

1 small square =

A

0.04 msec

40 sec

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26
Q

1 large square =

A

0.2 msec

200 sec

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27
Q

Normal QRS complex =

A

<120 msec

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28
Q

<120 msec is equivalent to

A

<3 small squares

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29
Q

QT interval is dependent on

A

Rate

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30
Q

QTc =

A

Qt interval adjusted for rate

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31
Q

QTc = QT interval at

A

60 bpm

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32
Q

How to work out rate of regular ECG

A

300/RR interval (num of large squares)

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33
Q

Bradycardia =

A

< 60 bpm

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34
Q

Regular QRS
P wave in front of each
Normal AV delay
<60 bpm

A

Sinus bradycardia

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35
Q

Irregular QRS
P wave not in front of each
Abnormal AV delay
<60 bpm

A

Heart block

36
Q

Causes of sinus bradycardia =

A

Normal, athelete

Over medication

37
Q

What does a patient need after they survive asystole?

A

Pacemaker

38
Q

Heart block =

A

Block in the electrical conduction system

39
Q

Causes of heart block =

A

MI
Congenital
Meds
Surgery

40
Q

What degree of heart block is usually asymptomatic?

A

First degree heart block

41
Q

First degree heart block ECG:

A

QRS regular
P in front of ever QRS
PR interval prolonged

42
Q

2nd degree heart block is broken up into

A
Type 1 (Mobitz I)
Type 2 (Mobitz II)
43
Q

Mobitz I =

A

Electrical signals are delayed ore and more with each beat.

44
Q

ECG of mobitz I =

A

PR interval gets longer and longer
QRS irregular
P wave present
Ventricular rate slower than atrial

45
Q

Mobitz II is also known as

A

2:1 heart block

46
Q

Mobitz II ECG:

A

Bradycardia
QRS regular
2x P waves for every QRS

47
Q

Third degree heart block:

A

Atrial and ventriclar contractions completely unrelated. No atrial signals reach the ventricles.

48
Q

ECG of 3rd degree heart block =

A

QRS complex regular
No P wave in front of each QRS
Broad QRS

49
Q

Are QRS on 2rd degree hear block broad or narrow?

A

Broad

50
Q

A form of sick sinus syndrome in which the arrhythmia alternates between slow and fast heart rates. Often associated with ischemic heart disease and heart valve disease

A

Brady-tachy syndrome

51
Q

How to treat brady-tachy syndrome?

A

Bradycardia - pacemaker

Tachycardia - meds

52
Q

Management of sinus bradycardia =

A

Investigate and remove cause

Manage conservatively

53
Q

What can cause sinus bradycardia?

A

Beta blockers
Digoxin
Hypothyroidism

54
Q

what can cause heart block?

A

MI
Digoxin
Beta blockers
Rate-slowing Ca2+ channel blockers

55
Q

What supplies SAN?

A

Right coronary artery

56
Q

Emergency treatment of heart block:

A
  • Atropine
  • Isoprenaline
  • External pacing
57
Q

Atropine =

A

Stimulates AV node

58
Q

Isoprenaline =

A

Adrenaline

59
Q

What happens in bundle branch block?

A

One ventricle contracts before the others

60
Q

WiLLiAM

A

LBBB
W V1
M V6

61
Q

MaRRoW

A

RBBB
M V1
W V6

62
Q

Tachycardia =

A

> 100 bpm

63
Q

Regular QRS, <120 msec

<120 bpm

A

Sinus tachycardia

64
Q

Regular QRS
<120 msec
>140 bpm

A

SVT

65
Q

SVT =

A

Superior ventricular tachycardia

66
Q

QRS regular

<120msec wide

A

Ventricular tachycardia

67
Q

Saw tooth ecg

A

Atrial flutter

68
Q

Tomb stoning ECG

A

STEMI

69
Q

Treatment for atrial tachycardia =

A

Adenosine

70
Q

Adenosine =

A

Slows conduction through AV node

71
Q

Adenosine won’t work on

A

Atrial flutter

72
Q

What will adenosine do with atrial flutter

A

Will see the flutter waves

73
Q

Commonest sustained arrthymia =

A

Atrial fibrilation

74
Q

AF can cause

A

Stroke

Tachy-cardiomyopathy

75
Q

ECG for AF =

A

QRS complexes not regular
QRS complexes irregular
No P waves
Narrow complex

76
Q

What can cause VF?

A

Ventricular tachycardia

77
Q

Regular QRS

QRS <120 msec

A

Ventricular tachycardia

78
Q

Commonly seen in pre-existing bardycardia, especially if given class I anti-arrythmic

A

Polymorphic VT/Torsades de Pointes

79
Q

Torsades de pointes can be exacerbated by

A

Low K+

Low Mg2+

80
Q

Causes of sinus tachycardia =

A
Hyperthyroid
Anxiety
Heart failure
Hypovolemia
Septicaemia
81
Q

Management of SVT

A
  • Vagotonic manoevers

- Adenosine Iv

82
Q

Management of VT

A

Check for hypokalaemia, hypomagnesaemia
IV amiodarone
Electrical cardioversion

83
Q

Amiodarone =

A

Ca2+ channel blocker

84
Q

Management of atrial fibrilation =

A

Rhythm control - cardioversion
Ventriclar control - betablocker, digoxin, verapamil
Anti-thrombotic

85
Q

What score can assess risk of stroke?

A

CHADS2-VASC

86
Q

What is digoxin used for?

A

Atrial fibrilation