Ventricular tachycardia

Question 1

What is ventricular tachycardia?

Answer 1

a regular broad-complex tachycardia originating from a ventricular ectopic focus. Rate usually > 120 bpm.

Question 2

What is the aetiology of ventricular tachycardia?

Answer 2

Electrical impulses arise from a ventricular ectopic focus

Question 3

Summarise the epidemiology of ventricular tachycardia

Answer 3

Fairly common
A shockable rhythm seen in cardiac arrest patients
VT incidence peaks at middle age

Question 4

List 4 symptoms of ventricular tachycardia

Answer 4

Chest pain
Palpitations
Dyspnoea
Syncope

Question 5

What do the symptoms of VT mimic? Why?

Answer 5

Symptoms of IHD or haemodynamic compromise due to poor perfusion

Question 6

List 8 signs of ventricular tachycardia on physical examination

Answer 6

Respiratory distress 
Bibasal crackles  
Raised JVP  
Hypotension 
Anxiety  
Agitation 
Lethargy 
Coma

Question 7

What are 4 investigations for ventricular tachycardia?

Answer 7

ECG: difficult to distinguish between VT + SVT with aberrant conduction. If in doubt, treat as a VT
Electrolytes: derangement can cause arrhythmias
Drug levels: e.g. digoxin toxicity
Cardiac enzymes: e.g. troponins to check for recent ischaemic event

Question 8

how do you treat a haemodynamically unstable patient with ventricular tachycardia?

Answer 8

With pulse: cardioversion

Without pulse: defibrillation

Question 9

List 4 Risk Factors for VT

Answer 9

Coronary heart disease
Structural heart disease
Electrolyte deficiencies (e.g. hypokalaemia, hypocalcaemia, hypomagnesaemia)
Use of stimulant drugs (e.g. caffeine, cocaine)

Question 10

List 3 complications of VT

Answer 10

Congestive cardiac failure
Cardiogenic shock
VT may deteriorate into VF

Question 11

Summarise the prognosis of ventricular tachycardia

Answer 11

GOOD if treated RAPIDLY

Long-term prognosis depends on the underlying cause

Question 12

What is the presence of signs dependent on?

Answer 12

Degree of haemodynamic instability

Question 13

List 3 features of the ECG seen in VT

Answer 13

Rate > 100 bpm
Broad QRS complexes
AV dissociation

Question 14

What causative factors should you look for in patients with VT? How do you treat these?

Answer 14

Electrolyte abnormalities (e.g. hypokalemia): correct imbalances
Medication-induced QT prolongation: remove offending medication, digoxin immune fab (fragment antigen-binding) for digoxin toxicity

Question 15

How do you treat a haemodynamically stable patient with ventricular tachycardia?

Answer 15

Antiarrhythmics: lidocaine, procainamide, amiodarone

Cardioversion if medical therapy fails

Question 16

What are 3 long term therapies for VT?

Answer 16

ICD; indicated in case of VT that does not respond to therapy 
Catheter ablation 
Antiarrhythmics (usually class I or III)

Question 17

Which drug is contraindicated in broad complex tachycardia as can precipitate severe hypotension, ventricular fibrillation or cardiac arrest?

Answer 17

Verapamil
Do not know whether SVT or VT
(can only be used in SVT)

Question 18

What is Torsades de pointes?

Answer 18

A Polymorphic ventricular tachycardia a/w long QT interval
May deteriorate into VF + lead to sudden death

Question 19

Give 2 congenital causes of long QT

Answer 19

Jervell-Lange-Nielsen syndrome
Romano-Ward syndrome

Question 20

List 3 anti-arrhythmics that can cause long QT

Answer 20

Amiodarone
Sotalol
Class 1a antiarrhythmics: Lidocaine, Procainamide, Flecainide

Question 21

What electrolyte abnormalities cause long QT?

Answer 21

Hypocalcaemia
Hypokalaemia
Hypomagnesaemia

Question 22

What 3 conditions/ states can cause long QT?

Answer 22

Myocarditis
SAH
Hypothermia

Question 23

List 5 drugs/ classes that can cause long QT

Answer 23

TCAs
Antipsychotics
Chloroquine
Terfenadine
Erythromycin

Question 24

What is given in management of torsades de pointes?

Answer 24

IV Magnesium Sulphate