Third-degree atrioventricular block after supraclavicular brachial plexus block: A case report

Supraclavicular brachial plexus block is a widely used technique for achieving rapid and profound sensory and motor blockade of the upper limb.1–3 One of the described side effects of this procedure is Horner’s syndrome, which is characterized by the classic triad of ptosis, miosis, and ipsilateral anhidrosis. This results from a cervicothoracic sympathetic block at the level of the stellate ganglion, caused by the spread of local anesthetic (LA) through anatomically contiguous tissues, leading to dysfunction of a second-order (preganglionic) neuron of the oculosympathetic pathway.