Ventricular tachycardia

Question 1

Define:

Answer 1

• A regular broad-complex tachycardia abnormally originating from the ventricles. The rate is usually > 120 bpm.
• MEDICAL EMERGENCY

Question 2

Aetiology:

Answer 2

• Electrical impulses arise from a ventricular ectopic focus – an excitable group of cells within the atria/ventricles which cause a premature heart beat outside the normally functioning circulation
• Can impair cardiac output causing hypotension, collapse and acute cardiac failure.

Question 3

Risk factors:

Answer 3

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

Question 4

Epidemiology:

Answer 4

• Fairly common
• It is one of the shockable rhythms that is seen in cardiac arrest patients
• VT incidence peaks in the middle decades of life

Question 5

Symptoms:

Answer 5

• Symptoms of ischaemic heart disease or haemodynamic compromise due to poor perfusion

o Chest pain
o Palpitations
o Dyspnoea
o Syncope

Question 6

Signs:

Answer 6

•	Signs are dependent on the degree of haemodynamic instability
o	Respiratory distress
o	Bibasal crackles 
o	Raised JVP 
o	Hypotension
o	Anxiety 
o	Agitation
o	Lethargy
o	Coma

Question 7

Investigations:

Answer 7

o ECG (can look similar to SVT):
• Rate > 100 bpm
• Broad QRS complexes
• AV dissociation
• Electrolytes - derangement can cause arrhythmias
• Drug levels - e.g. check for digoxin toxicity
• Cardiac enzymes - e.g. troponins to check for recent ischaemic event

Question 8

Management:

Answer 8

• ABC approach
• CHECK WHETHER THE PATIENT HAS A PULSE OR NOT
• Pulseless VT - follow advanced life support algorithm
• Unstable VT - reduced cardiac output

o Synchronised DC shock
o Correct electrolyte abnormalities
o Amiodarone
• Stable VT

• Implantable Cardioverter Defibrillator (ICD)
o ICD is considered if:
• Sustained VT causing syncope
• Sustained VT with ejection fraction < 35%
• Previous cardiac arrest due to VT or VF
• MI complicated by non-sustained VT

Question 9

Complications:

Answer 9

• Congestive cardiac failure
• Cardiogenic shock
• VT may deteriorate into VF

Question 10

Prognosis:

Answer 10

• GOOD if treated RAPIDLY

* Long-term prognosis depends on the underlying cause