6th March 2024

Ventricular Tachycardia (VT)

VT is a broad, complex tachycardia originating from the ventricles. It is sustained if it lasts more than 30s or non-sustained if it lasts between 3 beats and 30s. Risk factors for VT include structural heart disease, typically 48 hours after or even many years following acute ischaemic events and previous cardiac surgery. VT in younger patients is likely a consequence of a cardiac genetic syndrome. VT may present with cardiac arrest, syncope, chest pain and breathlessness. 

When QRS complexes are similar in morphology they are monomorphic, or polymorphic if they vary, the latter has an increased risk to progress to ventricular fibrillation. Identifying VT can be challenging and in the event of a cardiac arrest, a broad complex tachycardia should be treated as such. The following ECG features make VT more likely: 

• AV dissociation
• Capture beats 
• Fusion beats
• Very broad complex (>140ms)
• Positive/negative concordance across chest leads and extreme axis deviation. 

An important mantra to remember is that a regular broad complex tachycardia is VT until proven otherwise; if in doubt, treat any broad complex tachycardia as VT.

Management is with drug therapy including intravenous Amiodarone and Lidocaine if the patient is haemodynamically stable. In sustained VT with haemodynamic compromise, urgent DC cardioversion is warranted. Verapamil is contraindicated as it can lead to further clinical deterioration. If there is no obvious precipitating cause, consideration should be made for ICD insertion for secondary prevention.