Ventricular Tachycardia

Question 1

Define Ventricular Tachycardia

Answer 1

Ventricular rhythm >100bpm described as a regular broad complex tachycardia

Sustained: lasts at least 30s or required termination
Non-sustained: at least 3 beats that spontaneously resolves within 30s
Torsades de pointes (TdP): polymorphic VT with “twisting” morphology on ECG in the setting of QT prolongation

Question 2

Aetiology of Ventricular Tachycardia

Answer 2

Underlying IHD or non-ischaemic cardiomyopathy
Associated with CAD
May be idiopathic
Developing world: infection and cardiomyopathy e.g. Chagas’ disease

Question 3

Risk factors for Ventricular Tachycardia

Answer 3

Coronary artery disease
Acute MI 
Left ventricular systolic dysfunction 
Hypertrophic cardiomyopathy 
Long QT syndrome, Short QT syndrome 
Brugada syndrome 
WPW syndrome 
Electrolyte imbalance, esp. hypokalaemia and hypomagnesaemia
Drug toxicity 
Chagas’ disease

Question 4

Symptoms of Ventricular Tachycardia

Answer 4

Syncope or pre-syncope
Unconsciousness
Light-headedness and dizziness
Chest discomfort 
Dyspnoea

Question 5

Signs of Ventricular Tachycardia on examination

Answer 5

Tachycardia 
Hypotension
Weak pulse
Airways compromise: strider, apparent obstruction to breaths
Diminished responsiveness
Resp. Distress
Bi-basal crackles 
Raised JVP 
Anxiety/agitation

Question 6

Investigations for Ventricular Tachycardia

Answer 6

PULSELESS -> CARDIAC ARREST

ECG: broad-complex tachycardia, regular rhythm, each QRS the same
(Torsades de pointes) = “twisting” pattern

Electrolytes: check for cause
Troponin I: elevated in MI
CK-MB: elevated in MI

Echo: Depressed LV function and evidence of structural disease or hypertrophic cardiomyopathy
Cardiac MRI: scar, fibro-fatty infiltration of myocardium

Cardiac catheterisation: coronary artery obstruction

Question 7

Management of Ventricular Tachycardia

Answer 7

Pulseless VT: CARDIAC ARREST

1. CPR and defibrillation 30:2
2. UN-synchronised shock
3. Adrenaline 1mg IV every 3-5 minutes after the second shock
4. Consider amiodarone 400mg IV after the 3rd defibrillation attempt
5. Consider Mg surface 2g IV

Pulse present:

1. Synchronised cardioversion
2. Amiodarone 300mg IV push
3. Correct electrolyte imbalances

Haemodynamically stable
1. Amiodarone 150mg IV infusion over 10 minutes OR lidocaine
Correct electrolyte imbalances
2nd line: synchronised cardioversion

Question 8

Management for Torsades de pointes

Answer 8

1. Mg surface IV 1-2mg 
Withdraw offending drugs 
Correct electrolyte abnormalities
Is opera line IV
Pacing: non-idiopathic: implantable cardioverter defibrillator | idiopathic: consider catheter ablation

Question 9

Complications of Ventricular Tachycardia

Answer 9

Ventricular fibrillation
Sudden Cardiac death 
Cardioverter defibrillator infection 
Cardiomyopathy 
Amiodarone-induced thyroid dysfunction