Differentiating SVT from VT

Features that favour VT are :

QRS of > 140ms, cannon a waves on JVP fusion and/or capture beats dissociated p waves,

history of ischaemic heart disease,

right bundle branch block with left axis deviation, concordance of the QRS complexes in the chest leads HR >170 beats per minute.

In a patient who is stable with sustained ventricular tachycardia, the options are intravenous lignocaine, intravenous amiodarone. IV magnesium sulphate (18 / 20 mmols or 5g) is often helpful in helping to cardiovert. If the patient were unstable then he needs to be DC cardioverted immediately (with or without general anaesthetic).