arrythmias Flashcards

1
Q

what is an arrythmia

A

abnormal heart rythm

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2
Q

why do arrithmyas happen

A

interuption to normal electrical signals that coordinate contraction of heart muscle

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3
Q

how can the 4 cardiac arrest rhythms be classified

A

shockable - defib may be effective

non-shockable

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4
Q

cardiac arrest rhythms: shockable rhythms

A

ventricular tachycardia

ventricular fibrillation

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5
Q

cardiac arrest rhythms: non-shockable

A

pulseless electrical activity (all electrical activity except VF/VT, incl sinus rhythm without pulse)
asystole

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6
Q

tachycardia treatment summary: unstable patient

A
  • consider up to 3 synchronised shocks

- consider consider amiodarone infusion

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7
Q

tachycardia treatment summary: stable patient with narrow QRS complex

A

AF - beta blocker or CCB
atrial flutter - beta blocker
SVT: vagal manouvers, adenosine

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8
Q

tachycardia treatment summary: stable patient w broad QRS

A

VT or unclear - amiodarone infusion

SVT w bundle branch block - treat as per normal SVT

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9
Q

atrial flutter

A

caused by a re-enterant rhythm in either atrium
electrical signal re-circulates in a self-perpetuating loop due to extra pathway
signal goes round and round without interuption

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10
Q

atrial flutter: atrial and ventricular bpm

A

atrial contraction 300bpm

signal makes way to ventricles every 2nd lap due to long AV node refractory period - 150bpm ventricular contraction

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11
Q

atrial flutter: ECG

A

‘sawtooth appearance’

p wave after p wave

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12
Q

atrial flutter: assoc conditions

A

htn
IHD
cardiomyopathy
thyrotoxicosis

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13
Q

atrial flutter: Mx

A

rate/rhythm control - beta blockers or cardioverison
treat underlying condition
radiofrequency ablation of re-enterant system
anticoagulation based on CHADVASC

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14
Q

supraventricular tachycardia

A

electrical signal re-entering atria from ventricles

  • electrical signal finds way back from v to atria
  • once signal back in atria it travels back through AV node –> v contraction
  • self-perpetuating elec loop
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15
Q

SVT ECG

A

fast narrow QRS complex tachycardia

looks like QRS complex immediately followed by T wave

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16
Q

paroxysmal SVT

A

SVT reoccurs and remits in same patient over time

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17
Q

types of SVT: atrioventricular nodal re-enterant tachycardia

A

when the re-entry point is back through AV node

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18
Q

types of SVT: atrioventricular re-entarent tachycardia

A

when re-entry point is an accessory pathway (wolf-parkinson-white syndrome)

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19
Q

types of SVT: atrial tachycardia

A

electircal signal originates in atria somewhere other than SA node

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20
Q

acute management of stable pt w SVT

A

stepwise approach with cont. ECG monitoring

  1. valsalva maneouvre
  2. carotid sinus massage - massage carotid on one side w fingers
  3. adenosine
  4. alt to adenosine –> verapamil
  5. dirrect current cardioversion
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21
Q

adenosine

A

works by slowing cardiac conduction 1ry through AV nose

interupts AV node/accessory pathway during SVT and ‘resets’ back to sinus rhythm

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22
Q

how is adenosine given

A

as rapid bolus inot a large proximal cannula to ensure it reaches heart with enough impact to interupt pathway

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23
Q

what happens after initial adenosine administration

A

often cause breif period of asystole or bradycardia however it is metabolised quickly and sinus rhythm should return

24
Q

when to avoid adenosine

A
asthma 
COPD 
heart failure 
heart block 
severe hypotension
25
Q

long term management of pt w paroxysmal SVT

A

medication - beta blockers, CCB, amiodarone

radiofrequency ablation

26
Q

wolf-parkinson white syndrome

A

extra elcectrical pathway connecting atria and ventricles

27
Q

wolf-parkinson white syndrome: what is extra pathway often called

A

bundle of kent

28
Q

wolf-parkinson white syndrome: definitive treatment

A

radiofrequency ablation of accessory pathway

29
Q

wolf-parkinson white syndrome: ECG changes

A

short PR interval
wide QRS
delta wave - slurred upstroke on QRS

30
Q

radiofrequency ablaion can be curative for certain arrythmias caused by abnormal electrical pathways, incl…

A

AF
atrial fluter
SVT
WPW syndrome

31
Q

Torsades de pointes

A

type of polymorphic ventricular tachycardia

stimulate recurrent contractions withut normal repolarisation

occurs in pt w prolonged QT interval

32
Q

Torsades de pointes: ECG

A
  • QRS twist around baseline
  • QRS get progressively shortet
  • prolonged QT internal
33
Q

prolonged QT interval

A

ECG finding of prolonged repolarisation after contraction

34
Q

afterdepolarisations

A

wait longer time to repolarise causes random spontaneous depolarisation in some myocytes

abnormal depilatisations pripr to repol

35
Q

clinical course of Torsades de pointes

A

either terminate spontaneously

progress to VT

36
Q

causes of prolonged QT

A

long QT syndrome
medicatins: antipsychotics, citalopram, amiodarone, macrolide antibs
electrolyte disturbance - hypokalaemia, hypocalcaemia

37
Q

Torsades de pointes: acute Mx

A
correct cause - electrolyte disturbance or meds
magnesium infusion (even if have normal Mg) 
defibrillation if VT occurs
38
Q

Torsades de pointes: longterm Mx

A
  • avoid meds that prolong QT
  • correct electrolyte disturbances
  • beta blockers
  • pacemaker or implantable defib
39
Q

ventricular ectopics

A

premature ventricular beats caused by random electrical discharges from outside atria

40
Q

ventricular ectopics: presentation

A

random, brief palpitations

41
Q

ventricular ectopics: ECG

A

individual random, abdnormal, broad QRS complexes

42
Q

ventricular ectopics: bigeminy

A

when V ectopics happen to frewuently that they happen after every sinus beat

ECG normal sinus beat followed by ectopic

43
Q

ventricular ectopics: Mx

A
  • check bloods for anaemia, electrolyte disturbance, thyroid disease
  • reassure and no Rx if healthy
  • seek advice if background heart disease or concerning features e.g. chest pain, murmur
44
Q

AV node blocks

A

heart block

45
Q

1st degree heart block

A

delayed atrioventricualr conduction through AV node

despite this, every atrial impulse leads to ventric contraction –> every p wave results in QRS

46
Q

1st degree heart block ECG

A

PR interval > 0.2s

1 big square

47
Q

second degree heart block

A

some of atrial impulses do not make it through AV nodes to ventricles
–> instances where P wave doesnt lead to QRS

several types

  • mobitz T1
  • mobitz T2
  • 2:1 block
48
Q

second degree heart block: Mobitz type 1

A

atrial impulses become gradually weaker until it does not pass through AV node
after failure, atrial impulses become strong again and cycle repeats

49
Q

second degree heart block: Mobitz type one ECG

A

increasing PR interval until P wave no longer conduct –> absent QRS

50
Q

second degree heart block: Mobitz type 2

A

there is intermitted failure of AV conduction –> missing QRS

PR interval normal

risk of asystole

51
Q

second degree heart block: 2:1 block

A

there are 2 p waves for each QRS

every 2nd P wave is not strong enough to stimulate QRS

52
Q

3rd degree heart block

A

complete heart block

no observable relationship between P waves and QRS

signif risk of asystole

53
Q

Rx of bradycardias/AV node blocks: stable

A

observe

54
Q

Rx of bradycardias/AV node blocks: unstable or risk of asystole

A
  1. atropine 500mcg IV

no improvement>

  1. atropine 500mcg IV
  2. other inotropes
  3. transcutaneous cardiac pacing
55
Q

Rx of bradycardias/AV node blocks: high risk of asystole or prev asystole

A
  • temp transvenous cardiac pacing

- permanent implantable pacemaker

56
Q

atropine

A

antimuscarinic medication
works by inhibiting parasympathetic NS

–> pupil dilation, urinary retention, dry eyes, constipation