Broad complex tachycardias Flashcards
Give examples of broad complex tachycardia
Ventricular tachycardia: regular
Torsafes de pointes
SVT with aberrant conduction e.g. AF with BBB: irregular rhythm
Pre-excited tachycardia with underlying WPW
What is the difference between sustained and non-sustained VT
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
Aetiology of ventricular tachycardia
Underlying IHD or non-ischaemic cardiomyopathy
Coronary artery disease
Idiopathic
Developing world - infectious and cardiomyopathy play a significant role e.g. Chagas disease
Risk factors for ventricular tachycardia
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
ECG changes in ventricular tachycardia
Broad complex tachycardia
Regular rhythm
every QRS is the same
ECG changes in torsades de pointes
Polymorphic VT
Twisting morphology with QT prolongation
Management for unstable ventricular tachycardia
- A-E
- Look for a pulse (no pulse → arrest protocol)
- Supportive
- Sats <90 > oxygen
- IV access
- 12 lead ECG - Stable or unstable (shock, chest pain or ischaemia on ECG, heart failure, syncope)
- Sedation and seek senior help
- SYNCHRONISED DC shocks up to 3x
- 120-150J
- 150-360J x2
- Synchronised to R waves - Correct any electrolyte abnormalities
- central line → amiodarone 300mg IV over >20 minutes → shock → 900mg over 24h
Refractory: procainamide, overdrive pacing
Management for stable ventricular tachycardia
- A-E
- Look for a pulse (no pulse → arrest protocol)
- Supportive
- Sats <90 > oxygen
- IV access
- 12 lead ECG - Stable or unstable (shock, chest pain or ischaemia on ECG, heart failure, syncope)
- Correct any electrolyte imbalances, esp. hypoK, Mg, Ca
- 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)
Management for pulseless VT
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
Management for Torsade de pointes
- A-E
- Look for a pulse (no pulse → arrest protocol)
- Supportive
- Sats <90 > oxygen
- IV access
- 12 lead ECG - Stable or unstable (shock, chest pain or ischaemia on ECG, heart failure, syncope)
- Magnesium sulfate IV 1-2g
- Withdraw offending drugs
- Correct electrolyte abnormalities
- Isoprenaline IV
- Pacing
Management for on-going VT
non-idiopathic → implantable cardioverter defibrillator (ICD) | mexiletine OR flecainide | catheter ablation
Idiopathic → refer | metoprolol | catheter ablation | mexiletine OR flecainide
What medication is contraindicated in broad complex tachycardias
Verapamil