A 53 year old man presents with left sided tinnitus and slight unsteadiness for 1 year.

During the same period, he experienced pain in his right arm following muscular exertion, which was completely relieved by rest. He also experienced numbness in the right upper arm.

His medical and surgical histories are unremarkable. His family history is significant for coronary artery disease in his father and older brother.

He stopped smoking 2 years ago, and has a total smoking history of 10 pack years. He only drinks socially.