In others words, longer acting, highly protein bound and lipid soluble agents appear to be more toxic than those of lesser potency.
Local anesthetics work by blocking impulse conduction along nerves.
They have similar action in other impulse conducting organs such as the brain and heart. Relative potency for CVS toxicity again seems to follow the relative anesthetic potency. More potent agents, such as bupivacaine have been shown to be more cardiotoxic than less potent agents such as lidocaine. There have been laboratory and clinical reports of sudden acute CVS toxicity associated with clinically acceptable dosages, which included ventricular arrhythmias, fibrillation and death. The anesthetic technique should be designed to minimise the risk of accidental over-dosage.