Broad complex tachycardias Flashcards

1
Q

Give examples of broad complex tachycardia

A

Ventricular tachycardia: regular
Torsafes de pointes
SVT with aberrant conduction e.g. AF with BBB: irregular rhythm
Pre-excited tachycardia with underlying WPW

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2
Q

What is the difference between sustained and non-sustained VT

A

Sustained: Lasts at least 30 seconds or requires termination earlier due to instability
Non-sustained: Lasting for at least 3 beats that spontaneously resolves within 30 seconds

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3
Q

Aetiology of ventricular tachycardia

A

Underlying IHD or non-ischaemic cardiomyopathy
Coronary artery disease
Idiopathic
Developing world - infectious and cardiomyopathy play a significant role e.g. Chagas disease

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4
Q

Risk factors for ventricular tachycardia

A

Coronary artery disease
IHD
Ventricular systolic dysfunction
Hypertrophic cardiomyopathy
SHORT/long QT syndrome
Ventricular pre-excitation e.g. WPW syndrome
Electrolyte imbalance, especially hypokalaemia and hypomagnesaemia
Brugada syndrome
Chagas disease

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5
Q

ECG changes in ventricular tachycardia

A

Broad complex tachycardia
Regular rhythm
every QRS is the same

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6
Q

ECG changes in torsades de pointes

A

Polymorphic VT
Twisting morphology with QT prolongation

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7
Q

Management for unstable ventricular tachycardia

A
  1. A-E
  2. Look for a pulse (no pulse → arrest protocol)
  3. Supportive
    - Sats <90 > oxygen
    - IV access
    - 12 lead ECG
  4. Stable or unstable (shock, chest pain or ischaemia on ECG, heart failure, syncope)
  5. Sedation and seek senior help
  6. SYNCHRONISED DC shocks up to 3x
    - 120-150J
    - 150-360J x2
    - Synchronised to R waves
  7. Correct any electrolyte abnormalities
  8. central line → amiodarone 300mg IV over >20 minutes → shock → 900mg over 24h

Refractory: procainamide, overdrive pacing

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8
Q

Management for stable ventricular tachycardia

A
  1. A-E
  2. Look for a pulse (no pulse → arrest protocol)
  3. Supportive
    - Sats <90 > oxygen
    - IV access
    - 12 lead ECG
  4. Stable or unstable (shock, chest pain or ischaemia on ECG, heart failure, syncope)
  5. Correct any electrolyte imbalances, esp. hypoK, Mg, Ca
  6. Assess rhythm
    - Regular → central line → amiodarone 300mg IV over >20 minutes → 900mg over 24h
    No success or becomes unstable → sedation → SYNCHRONISED DC shock 150-200J → 150-360J x2 (biphasic)
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9
Q

Management for pulseless VT

A

Cardiac arrest protocol
1. CPR and Defibrillation
2. 30:2, UNSYNCHRONISED Debrillation after 5 cycles
- 120-200 J for biphasic defibrillators and 360 J for monophasic defibrillators
3. Adrenaline 1mg IV every 3-5 minutes
- After the second shock
- Follow with 5 cycles
4. Consider amiodarone 300mg IV
5. Consider magnesium sulfate 2g IV

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10
Q

Management for Torsade de pointes

A
  1. A-E
  2. Look for a pulse (no pulse → arrest protocol)
  3. Supportive
    - Sats <90 > oxygen
    - IV access
    - 12 lead ECG
  4. Stable or unstable (shock, chest pain or ischaemia on ECG, heart failure, syncope)
  5. Magnesium sulfate IV 1-2g
  6. Withdraw offending drugs
  7. Correct electrolyte abnormalities
  8. Isoprenaline IV
  9. Pacing
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11
Q

Management for on-going VT

A

non-idiopathic → implantable cardioverter defibrillator (ICD) | mexiletine OR flecainide | catheter ablation

Idiopathic → refer | metoprolol | catheter ablation | mexiletine OR flecainide

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12
Q

What medication is contraindicated in broad complex tachycardias

A

Verapamil

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