Arrhythmias Flashcards

1
Q

How can arrhythmias be divided?

A

Tachyarrhythmia and Bradyarrhythmia

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2
Q

List 4 examples of Bradyarrhythmias

A
  1. Sick sinus syndrome
  2. Sinus bradycardia
  3. Heart blocks
  4. BBB
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3
Q

What is sick sinus syndrome?

A

Sinus node becomes dysfunctional due to sinus node fibrosis.

Typically affects the elderly

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4
Q

How does sick sinus syndrome affect the rate/rhythm of the heart?

A

Can cause sinus bradycardia, pauses, sinus tachycardia or AF

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5
Q

What does this ECG of sick sinus syndrome show?

A

“pauses” due to sinus exit block/sinus arrest

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6
Q

Sick sinus syndrome causes chronotropic incompetence, what does this mean?

A

Inability to increase and maintain HR appropriately during exercise

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7
Q

Treatment of sick sinus syndrome (3)

A
  1. Conservative - asymptomatic
  2. Correct reversible causes
  3. Pacemaker for symptomatic bradycardia or sinus pauses
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8
Q

What is heart block?

A

Communication problem between he atria and ventricle

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9
Q

What is first degree heart block?

A

P-R interval elongation 0.20 seconds (5 small/1 big square) due to conduction delay at the AV node

All signals reach the ventricles

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10
Q

What are the 2 types of second degree heart block?

A
  1. Mobitz type 1 (Type 1) ‘Wenkebach’
  2. Mobitz type 2 (Type )
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11
Q

Compare Mobitz 1 vs 2

A

Excitation sometimes fails to pass through the AV node or bundle of His

Type 1: P-R interval elongation, then QRS dropped

Types 2: Constant P-R interval, then QRS dropped

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12
Q

What is Complete (third degree) heart block?

A

Atrial contractions are normal but NO electrical activity conveyed to the ventricles

Ventricles generate their own signal through ectopic pacemaker

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13
Q

Treatment of heart block?

A
  1. Conservative if asymptomatic and not high risk
  2. Correct reversible causes
  3. Pacemaker if symptomatic or high degree block
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14
Q

What is the biggest risk of complete degree heart block?

A

Risk of sudden death

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15
Q

Are pacemakers used to treat brady, tachy or both types of arrythmias?

A

Bradyarrhythmias

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16
Q

List patient groups who are high risk for asystole

A
  1. Mobitz Type 2
  2. Complete heart block
  3. Previous asystole
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17
Q

Treatment of Bradycardias?

A
  1. First line: Atropine 500mcg IV
  2. No improvement: Repeat Atropine (total of 3mg) OR Adrenaline OR Transcutaneous cardiac pacing
  3. Transvenous cardiac pacing
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18
Q

What is Atropine

List 2 s/e

A

antimuscarinic - inhibits the PNS

S/e: pupil dilatation, urinary retention, dry eyes and constipation

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19
Q

List 4 examples of Tachyarrhythmias

A
  1. AF or Atrial flutter
  2. SVT
  3. VT or VF
  4. Sinus tachycardia
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20
Q

List 4 risk factors for atrial flutter

A
  1. Obesity
  2. Hypertension
  3. Drugs (alcohol)
  4. Structural heart disease (valves, congenital, cardiomyopathy)
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21
Q

What ECG change is characteristic of Atrial fibrillation

A

Absent P waves

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22
Q

How does AF present?

A
  1. palpitations
  2. dyspnoea
  3. chest pain
  4. an irregularly irregular pulse
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23
Q

What are the two key parts of managing patients with AF

A
  1. Rate/rhythm control
  2. Reducing stroke risk
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24
Q

How do assess risk of stroke in a patient with AF

What values indicate anticoagulation is required?

A

CHA2DS2-VASC score

Anticoagulation if >1 male or >2 female

25
Q

How is rate control achieved in AF

A

First line: BB or a rate-limiting CCB (e.g. diltiazem)

Second line is combination therapy with any 2 of the following:

  • a betablocker
  • diltiazem
  • digoxin
26
Q

What is a contraindication to use of BB in AF?

A

Asthma

27
Q

How is rhythm control achieved in AF

A

Cardioversion

28
Q

When is a patient with AF eligible for cardioversion

A
  1. cardioversion if less than 48 hours OR
  2. anticoagulation for 3-4wks prior to attempting cardioversion
29
Q

Why do we NOT cardiovert an patient who had had AF symptoms >48hrs?

A

If a thrombus has formed, the moment patient switches from AF to sinus rhythm there is a high risk of embolism leading to stroke

30
Q

Like 4 causes of Atrial flutter

A

Same as AF

31
Q

Compare the risk of stroke in AF vs atrial flutter

A

AF higher risk

32
Q

Compare treatment of AF vs atrial flutter

A

Same rate control vs. rhythm control strategy

Atrial flutter harder to rate control but easier to cardiovert or ablate

33
Q

What is SVT

A

Regular narrow complex tachycardias which originate above the ventricle

34
Q

What are the 2 types of SVT?

A

AVNRT and AVRT

35
Q

What is AVNRT

A

AV nodal re-entry tachycardia

Rapidly firing circuit within the AV node

36
Q

What is AVRT?

A

Atrioventricular re-entry tachycardia

uses an accessory pathway (a “short circuit” between atrium and ventricle) and the AV node to make a circuit

37
Q

Which type of SVT is more common?

A

AVNRT

38
Q

What are the 2 ways we can classify AVRT

A

“orthodromic” (going through AV node in normal direction)

“antidromic” (going through AV node backwards)

39
Q

Treatment of SVT

A

First line: vagal manoeuvres (carotid sinus massage, valsalva)

Second line: adenosine

40
Q

What is Wolff-Parkinson-White?

A

Clinical syndrome of tachyarrhythmias and pre-excitation on ECG

41
Q

What is the characteristic ECG changes of WPW

A

Delta wave and P-R shortening

42
Q

Treatment of WPW

A

Ablation of the bundle of kent

43
Q

What is VT and VF?

A

Regular broad-complex tachycardias originating in ventricles

44
Q

How do VT and VF present?

A
  1. palpitations
  2. heart failure/shock
  3. syncope
  4. sudden death
45
Q

How dangerous is VT vs VF?

A

VT is usually dangerous (though not always – “normal heart VT”)

VF is always dangerous

46
Q

Treatment of VT and VF?

A

Hemodynamically stable: IV amiodarone

Hemodynamically unstable: Immediate cardioversion

47
Q

What are the two types of VT?

A
  1. Monomorphic VT: most commonly caused by MI
  2. Polymorphic VT (subtype is torsades de pointes)
48
Q

What is Monomorphic Ventricular Tachycardia?

A

Usually caused by a scar in the ventricle

Most commonly prior MI but can be due to scarring from other processes (e.g. cardiomyopathy, sarcoidosis)

49
Q

What is PVT

A

Usually caused by ectopic beat in vulnerable period (“R-on-T”)

Usually no cardiac output

50
Q

What is Torsades-de-pointes

A

‘Twisting of the points’ - Subtype of PVT

Characterised by a long QT interval due to rotating QRS axis

51
Q

How do you treat Torsades de pointes?

A

IV magnesium sulphate

52
Q

List 4 causes of PVT

A

Anything causing QT prolongation

eg. electrolyte abnormalities (low K/Ca/Mg), acute ischaemia, bradycardia, long QT syndrome

53
Q

Treatment of PVT?

A

Often self-terminating

Otherwise needs cardioversion with thump or DC shock

Treatment involves correcting cause and overdrive pacing

54
Q

List 4 causes of VF

A
  1. myocardial acidosis
  2. acute ischaemia (i.e. current MI)
  3. ventricular scarring
  4. electrolyte abnormalities
55
Q

Treatment of VF

A

IMMEDIATE defibrillation or death will ensue

56
Q

Following restoration of sinus rhythm, what is generally offered to most patients with VT/VF

A

ICD

57
Q

Revise Tachycardia treatment algorithm

A
58
Q

What are the 2 ways Cardioversion is achieved?

A
  1. Pharmacological CV: Flecanide, Amioderone
  2. Electrical CV
59
Q

What are the 4 Cardiac Arrest Rhythms

Incl which are shockable/non-shockable

A

Shockable rhythms: VT and VF

Non-shockable rhythms: PEA and Asystole