Ventricular Tachycardia

Question 1

Definition

Answer 1

A regular broad-complex tachycardia originating from a ventricular ectopic focus. The rate is usually > 120 bpm.

Question 2

Aetiology

Answer 2

Electrical impulses arise from a ventricular ectopic focus

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

Presenting symptoms

Answer 5

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

· Symptoms:

o Chest pain
o Palpitations
o Dyspnoea
o Syncope

Question 6

Signs on physical examination

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

· ECG
o It can sometimes be difficult to distinguish between VT and SVT with aberrant conduction
o If in doubt, treat as a VT
o ECG Features:
· 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 plan

Answer 8

· ABC approach

· CHECK WHETHER THE PATIENT HAS A PULSE OR NOT

· 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

Management plan (pulseless VT)

Answer 9

Pulseless VT - follow advanced life support algorithm

Question 10

Management plan (unstable VT)

Answer 10

· Unstable VT - reduced cardiac output

o NOTE: VF and pulseless VT require defibrillation (unsynchronised), but other VTs can be treated with synchronised cardioversion

o Correct electrolyte abnormalities

o Amiodarone

Question 11

Management plan (stable VT)

Answer 11

· Stable VT

o These patients DO NOT experience symptoms of haemodynamic compromise

o Correct electrolyte abnormalities

o Amiodarone

o Synchronised DC shock (if steps above are unsuccessful)

Question 12

Possible complications

Answer 12

· Congestive cardiac failure

· Cardiogenic shock

· VT may deteriorate into VF

Question 13

Prognosis

Answer 13

· GOOD if treated RAPIDLY

· Long-term prognosis depends on the underlying cause