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Year 3 - CR > Cardiac Arrhythmias > Flashcards

Cardiac Arrhythmias Flashcards

1
Q

what should you look for in your general approach to arrhythymias

A
  • whether the heart rhythm is fast (tachycardia) or slow (bradycardia)
  • you should see whether the patient is presenting acutely or electively
  • you should see whether the arrhythmia is primary (the heart) or secondary (something else)
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2
Q

what is tachycardia

A

greater than 100bpm

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3
Q

What is bradycardia

A

less than 60bpm

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4
Q

How do you assess the patient with tachycardia and what do you do in unstable tachycardia

A
  • Monitor SpO2 and give oxygen if they are hypoxic
  • monitor ECG and BP and record 12 lead ECG
  • obtain IV access
  • identify and treat reversible causes

adverse features

  • shock
  • MI
  • heart failure
  • Syncope
  • if you have these adverse features then this means that the tachycardia is unstable
  • if the tachycardia is unstable you should administer a synchronised DC shock up to 3 times
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5
Q

What are the adverse features of tachycardia

A
  • shock
  • MI
  • heart failure
  • Syncope
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6
Q

What do you do in stable tachycardia

A
  • Look to see if the QRS is narrow (at less than 0.12s)

-

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7
Q

What do you do in unstable tachycardia

A

adverse features

  • shock
  • MI
  • heart failure
  • Syncope
  • if you have these adverse features then this means that the tachycardia is unstable
  • if the tachycardia is unstable you should administer a synchronised DC shock up to 3 times
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8
Q

What determines the width of the QRS complex

A

using normal confusion system (his-purkinje system) to active ventricles
- tachycardia where ventricles are activated by a normal conduction system

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9
Q

Name how a narrow QRS complex is caused and define it

A
  • ECG shows a rate of greater than 100bpm and a QRS complex duration of less than 120ms
  • it is caused supra-ventricular tachycardia and this is due to a complication happening above the bundle of his and above the ventricles, occur when the ventricles are depolarised via normal conduction pathways
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10
Q

What is another name for a narrow QRS complex

A

Supra-ventricular tachycardia

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11
Q

Name the types of supra-ventricular tachycardia

A
  • Atrial fibrillation/flutter/tachycardia
  • Atrio-Ventricular Nodal Reentrant Tachycardia
  • Atrio-Ventricular Reentrant Tachycardia
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12
Q

Why are Atrial fibrillation/flutter/tachycardia

grouped together as a type of ventricular tachycardia

A
  • substrate from the arrhythmia originates from the atria themselves
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13
Q

What causes atrial flutter

A
  • Counter clockwise circuit going through the right atria
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14
Q

What does Atrial flutter look like on the ECG wave

A
  • Saw tooth P flutter waves - negative in the inferior leads
  • 150bpm is the ventricular rate
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15
Q

what causes atrial fibrillation

A
  • random depolarisation in different parts of the atrial fibrillation
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16
Q

What does the ECG look like of atrial fibrillation

A
  • RR intervals are irregular

- lack of P waves

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17
Q

Describe the treatment for atrial fibrillation in stages

A
  • Acute rate and rhythm control
  • manage precipitating factors - lifestyle changes, treatment of underlying cardiovascular conditions
  • assess stroke risk - oral anticoagulation in patients at risk for stroke
  • rate control therapy
  • antiarrhtymic drugs, cardioversion, catheter ablation, AF, surgery
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18
Q

Describe how you would decide what medication you would use for AF

A

if LVEF is greater than or equal to 40%

  • beta blocker or dilitiazem or verapamil
  • if this does not wokr add digoxin
  • initial resting heart rate target is less than 110bpm

If LVEF is less than 40% or if there are sings of congestive heart failure

  • smallest dose of beta blocker to achieve rate control
  • add digoxin
  • initial resting heart rate target is less than 110bpm

For both of these

  • avoid bradycardia
  • perform echocardiogram to determine further management/choice of maintenance therapy
  • consider need for anticoagulation
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19
Q

Describe how the CHADVASC score works in assessing stroke risk in atrial firbillation

A
  • Congestive heart failure = 1
  • Hypertension = 1
  • Age 65-74 =1, over 75 = 2
  • Diabetes = 1
  • Stroke or prior TIA = 2
  • Vascular disease = 1
  • S – female sex = 1
    If the score is 0 = then no treatment
    If the score is 1 = males: consider anticoagulation, females no treatment
    If score is 2 or more than offer anticoagulation
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20
Q

What is used to work out the risk of stroke occurring in atrial fibrillation

A

(CHADSVASC score)

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21
Q

How do you treat atrial fibrillation

A

Rate control
- either with a beta blocker or a rate limiting calcium channel blocker (e.g. dilimiazem)

Rhythm control
- either cardio version or drug induced cardioversion with amodiarone

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22
Q

What causes atrial ventricular node re-entry tachyarrthymia

A
  • this is a re-entrant circuit that develops around the AV node
  • re entry within the AV node
  • fast and regular
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23
Q

What happens in atrio-ventricular reentrant tachycardia

A
  • this occurs in patients with pre-excitation

- accessory pathway that allows electrical activity in the ventricle which occurs with the normal electrical pathway

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24
Q

What does an ECG look like in atrio-ventricular reentrant tachycardia

A
  • Delta wave
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25
Q

What is another word for atrio-ventricular reentrant tachycardia

A

Wolff-Parkinson white syndrome

  • pre-excited ECG
  • documented tachycardia/palpitation symptoms
  • orthodromic AVRT
    • the ventricle is activated down the pukinje his pathway and then goes up the accessory pathway
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26
Q

What happens in the orthodromic AVRT

A
  • the ventricle is activated down the pukinje his pathway and then goes up the accessory pathway
  • Narrow QRS complex
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27
Q

What happens in the antidromic AVRT

A

the ventricles are activated by the accessory pathway therefore the right side of the ventricle is activated first, the pathway then goes back up the bundle of His
- Broad QRS complex

28
Q

What happens when there is atrial fibrillation in the top chambers and conducts down

A
  • atrial fibrillation in the top chambers and is conducting down into the ventricles via the AV node and the accessory pathway
  • fast
  • broad
  • irregular
  • emergency - DC cardioversion and then need inpatient ablation
29
Q

What happens when you ablate the accessory pathway

A

Delta waves disappear

30
Q

What can you use to treat atrial ventricular node re-entry tachyarrthymia and atrio-ventricular reentrant tachycardia

A
  • both of these tachycardia depend on the node

- therefore any vagal termination with vagal manoeuvre and adenosine can terminate the tachycardia

31
Q

What happens if you have a narrow QRS complex and the rhythm is irregular

A
  • have a narrow QRS complex
  • If the rhythm is irregular it is probable AF
  • control rate with a beta blocker or dilitiazem
  • if in heart failure consider digoxin or amiodarone
  • assess thromboembolic risk and consider anticoagulant
32
Q

What happens if you have a narrow QRS complex and the rhythm is regular

A
  • Narrow QRS complex
  • rhythm is regular
  • vagal manoeuvres
  • adenosine 6mg rapid IV bolus - if no effect give 12mg if no effect give further 12 mg
  • monitor/record ECG continuously
  • check to see if sinus rhythm is achieved
  • if no seek expert help - could be a possible atrial flutter - control rate with something like a beta blocker
  • if yes
    probably re-entry paroxysmal SVT
  • record 12 lead ECG in sinus rhythm
  • if SVT recurs treat again and consider anti-arrhythmic prophylaxis
33
Q

What does if mean if you have broad complex tachycardia

A

= ECG shows a rate of greater than 100bpm and QRS complexes greater than 120ms
- ventricular activation not via normal specialised conduction system

34
Q

What happens in ventricular tachycardia

A
  • Ventricular tachycarida
  • this occurs in the ventricle when the ventricle is activated by somewhere else in the ventricle, now it is activated from one side to the other side resulting in a broad QRS complex
35
Q

What happens in SVT with abberancy

A
  • Bundle branch block causing QRS complex to become broad

- the bundle of his system does not work as it should

36
Q

describe what happens in paced rhythm

A
  • Paced rhythm

- place a pacing wire in the right ventricle and a pace rhythm

37
Q

describe what happens in excited to make the QRS complex look broad

A

delta wave can make the QRS complex look broad

38
Q

if the origin of the VT is

  • LV
  • RV or Septal LV
  • Lateral LV
  • RV or septal LV
  • apex
  • base
  • inferior
  • superior (outflow tract)

where is the ECG showin

A
  • LV = RBBB
  • RV or Septal LV = LBBB
  • Lateral LV = I, aVL ,negative
  • RV or septal LV = I, aVL, positive
  • apex = V3-V5, negative
  • base = V3-V5, positive
  • inferior = II, III, aVF, negative (superior axis)
  • superior (outflow tract) = II, III, aVF, positive (inferior axis)
39
Q

what can pinpoint on an ECG if the patient has ventricular tachycardia

A
  • Regular broad complex

Va dissociation

  • fusion beats
  • capture beats
  • independent P wave activity
  • ventricular concordance
  • bizarre frontal axis
  • very broad QRS
40
Q

What do you do if the broad QRS complex is regular

A

It is VT until proven otherwise
- amiodarone 300mg IV over 20-60 minutes then 900mg over 24 hours

If known to be SVT with bundle branch block
- treat as for regular narrow-complex tachycardia

41
Q

What do you do if the broad QRS complex is irregular

A
  • AF with bundle branch block – treat as for narrow complex tachycardia
  • Polymorphic VT e.g. Torsade de pointes – give IV magnesium
42
Q

If the bradycardia has no adverse features how do you treat

A

calculate if there is a risk of asystole

  • recent asystole
  • Mobitz II AV block
  • complete heart block with broad QRS complex
  • ventricular pause greater than 3 seconds

if no
- continue to observe

if yes 
Consider interim measures 
- Atropine 500mcg IV repeat to maximum of 3mg 
then give 
- transcutaneous pacing 
then give 
- isoprenaline 5mcgmin-1 IV 
- adrenaline 2-10mcgmin-1 IV 
- alternative drugs
  • Seek expert help - arrange transvenous pacing
43
Q

What puts you at risk of asystole if you have bradycardia

A
  • recent asystole
  • Mobitz II AV block
  • complete heart block with broad QRS complex
  • ventricular pause greater than 3 seconds
44
Q

Name the adverse features of bradycardia

A
  • shock
  • syncope
  • myocardial ischaemia
  • heart failure
45
Q

What happens if you have adverse features of bradycardia

A

adverse features

  • shock
  • syncope
  • myocardial ischaemia
  • heart failure

Yes

  • Atropine 500mcg IV repeat to maximum of 3mg
  • Then if this does not work then do transcutaneous pacing
  • if this does not work then isoprenaline/adrenaline infusion titrated to response

Yes
calculate if there is a risk of asystole
- recent asystole
- Mobitz II AV block
- complete heart block with broad QRS complex
- ventricular pause greater than 3 seconds

no
- continue observation

if no satisfactory response to atropine
Consider interim measures
- Atropine 500mcg IV repeat to maximum of 3mg
- Then if this does not work then do transcutaneous pacing
- if this does not work then isoprenaline/adrenaline infusion titrated to response

  • Seek expert help - arrange transvenous pacing
46
Q

what device treatment can you use for bradycardia

A

pacemaker - make sure that the heart rate never drops below a certain number

47
Q

What device can you use for VT/VF

A

ICD

48
Q

How does cardiac synchronisation devices work

A
  • special pacemakers - implanted to pace the heart at all times in a specific manner to make sure that the RV/LV work in function
  • BiV/CRT
49
Q

How do arrhythmias often present

A
  • Palpitations
  • chest pain
  • presyncope/syncope
  • hypotension
  • pulmonary oedema
50
Q

What tests should be carried out for someone with arrhythmias

A
  • FBC
  • U and Es
  • glucose
  • calcium, magnesium
  • TSH
  • ECG - look for signs of IHD, AF, short PR intervals, long QT intervals (metabolic imbalance, drugs, congenital), U waves (hypokalaemia)
  • can do a continuous ECG monitoring - Holter monitors or loop recorders
  • ECHO - structural heart disease
  • exercise ECG tests
51
Q

Name examples of broad complex tachycardia

A
  • Ventricular fibrillation
  • asystole
  • ventricular tachycardia
  • torsade de pointes
52
Q

What are the indications for permanent pacemaker

A
  • Complete av block (Stokes–Adams attacks, asymptomatic, congenital).
  • Mobitz type ii av block (p[link]).
  • Persistent av block after anterior mi.
  • Symptomatic bradycardias (eg sick sinus syndrome, p[link]).
  • Heart failure (cardiac resynchronization therapy).
  • Drug-resistant tachyarrhythmias.
53
Q

Name the neurological causes of collapse

A
  • hypoglycaemia
  • seizure
  • stroke
  • vasovagal
54
Q

Name the cardiovascular causes of collapse

A
  • postural hypotension
  • aortic stenosis
  • arrhythmia
55
Q

What is a vasovagal collapse occur in response to

A
  • occurs in response to stimuli such as emotion, pain, fear, prolonged standing
  • there is preceding nausea, pallor, sweat and closing visual fields
  • the collapse for 2 minutes
  • decrease in pulse and pupils are dilated
56
Q

How would you test for vasovagal collapse

A
  • Tilt-table test - if scope diagnosis is unclear
  • consider investigations to exclude other causes
  • ECG is normal
57
Q

What is cardioversion

A

= treatment that aims to get the abnormal heart rhythm (arrhythmia) back to a normal pattern
- done by sending electric shocks to the heart through electrodes placed o the chest

58
Q

Who is cardio version usually done to

A
  • atrial fibrillation

- atrial flutter

59
Q

What is ablation

A
  • It either uses heat (radiofrequency ablation) or freezing (cryoablation) on the area of the heart that is causing the abnormal heart rhythm
60
Q

what two scenarios is cardio version used in AF

A
  • As emergency if the patient is haemodynamically unstable

- Electrical or pharmacological cardioversion as an elective procedure where a rhythm control strategy is preferred

61
Q

describe how cardio version is used in AF before and after 48 hours

A

Onset <48 hours

  • If AF is less than 48 onset patients should be heparinised
  • Patients who have risk factors for ischaemic stroke should be pert on lifelong oral anticoagulation otherwise patients may be cardioverted using either DC cardioversion or amiodarone if strucual heart disease
  • Following cardioversion if AF is confirmed as being less than 48 hours duration then further anticoagulation is unnecessary

Onset >48 hours

  • If patient has been in AF for more than 48 hours then anticoagulation should be given at least 3 weeks prior to cardioversion
  • If there is a high risk of cardioversion failure then it is recommended to have at least 4 weeks amiodarone or sotalol prior to cardioversion
  • Following cardioversion patietns should be anticoagulated for at least 4 weeks
62
Q

How is torsade de pointes treated

A

IV magnesium

63
Q

What is torsade de pointes

A

type of ventricular tachycardia which is precipitated by prolongation of the QT interval

64
Q

When do you use rhythm control in AF first instead of rate control

A

coexistent heart failure, first onset AF or an obvious reversible cause

65
Q

What is normally first line treatment for AF rate or rhythm control

A

rate control unless

  1. coexist heart failure
  2. first onset AF
  3. Obvious reversible cause

Year 3 - CR (44 decks)

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