Ventricular Tachycardia Flashcards
What is the definition of ventricular tachycardia?
A regular broad-complex tachycardia originating from a ventricular ectopic focus. The rate is usually > 120 bpm.
What is the aetiology of ventricular tachycardia?
Electrical impulses arise from a ventricular ectopic focus
What are the risk factors associated with ventricular tachycardia?
Coronary heart disease
Structural heart disease
Electrolyte deficiencies (e.g. hypokalaemia, hypocalcaemia, hypomagnesaemia)
Use of stimulant drugs (e.g. caffeine, cocaine)
What is the epidemiology of ventricular tachycardia?
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
What are the presenting symptoms of ventricular tachycardia?
Symptoms of ischaemic heart disease or haemodynamic compromise due to poor perfusion
Symptoms:
- Chest pain
- Palpitations
- Dyspnoea
- Syncope
What are the signs of ventricular tachycardia?
Signs are dependent on the degree of haemodynamic instability
- Respiratory distress
- Bibasal crackles
- Raised JVP
- Hypotension
- Anxiety
- Agitation
- Lethargy
- Coma
What are the appropriate investigations for ventricular tachycardia?
ECG
- It can sometimes be difficult to distinguish between VT and SVT with aberrant conduction
- If in doubt, treat as a VT
- 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
What is the management plan for ventricular tachycardia?
ABC approach
CHECK WHETHER THE PATIENT HAS A PULSE OR NOT
Pulseless VT - follow advanced life support algorithm
Unstable VT - reduced cardiac output
- NOTE: VF and pulseless VT require defibrillation (unsynchronised), but other VTs can be treated with synchronised cardioversion
- Correct electrolyte abnormalities
- Amiodarone
Stable VT
- These patients DO NOT experience symptoms of haemodynamic compromise
- Correct electrolyte abnormalities
- Amiodarone
Synchronised DC shock (if steps above are unsuccessful)
Implantable Cardioverter Defibrillator (ICD)
- 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
What are the possible complciations of ventricular fibrilation?
Congestive cardiac failure
Cardiogenic shock
VT may deteriorate into VF
What is the prognosis for patients with ventricular fibrilation?
GOOD if treated RAPIDLY
Long-term prognosis depends on the underlying cause
