Ventricular tachycardia

Last modified: 29 October 2022, 2:12:24 PM AEDT

Gems / Priorities1 / 6

broad complex tachycardia DIFFERENTIAL:
1. VT
2. SVT with aberrant conduction due to BBB
3. SVT with aberrant conduction due to WPW
Brugada criteria = likely VT if
- 1:precordial concordance
  - leads V1-6 are all positive (R) or negative (QS)
  - no RS complexes
  - similar angle of depolarisation
- 2:Wide RS
  - very broad complexes > 160 ms = > 4 small boxes
  - ie. QRS > 0.16 (normal = 0.12 = 3 small boxes)
  - RS > 100 ms in ONE precordial lead
    - This is Brugada's sign
    - Start of R to bottom of S = the R-S interval
- 3:AV dissociation
  - P waves at different rate to QRS
- 4:Morphology
  - criteria for VT in V1-2 and V6
additional = likely VT if
- 1:Axis
  - North-west axis = extreme axis deviation
- 2:capture beats
  - occasional beats from SAN are conducted through to the ventricles
  - intermittent NORMAL QRS in midst of broad complexes
- 3:fusion beats
  - sinus and ventricular beat coincide, producing a hybrid complex of unusual appearance
aberrancy is rare in children
- wide complex tachycardia without p waves (or indepedent p waves) should be treated as VT

Definition / diagnostic criteria2 / 6

Investigations3 / 6

ECG
- usually 130-250 BPM
- wide abnormal complexes
- may cause inverted p waves (retrograde)
- LAD

Management4 / 6

anti-arrhythmics, eg. lidocaine, amiodarone
synchronised cardioversion
- Needs to be synchronised because there is still a QRS complex = ventricular depolarisation
- Only VF doesn't need synchronisation
cardiac pacing
prophylaxis
- anti-arrhythmics
- excision of ectopic focus
- ICD

Anaesthetic considerations5 / 6

Links / References6 / 6