The most cardiotoxic local anaesthetic is:
Bupivacaine is the most cardiotoxic and long acting amides. Inadveent injection of intravenous bupivacaine has been associated with frequent cardiotoxic reactions; ventricular tachycardia, fibrillation, and cardiac arrest. This is the main drawback of bupivacaine and for this reason bupivacaine is no longer used for intravenous regional anaesthesia. It is contraindicated in IV anesthesia due to cardiotoxicity.
Lignocaine
Bupivacaine
Prilocaine
Procaine