A patient in their mid-70s with a history of hypertension is brought in by medics for chest pain with onset about 45 minutes prior to arrival while he was getting dressed. His chest pain radiates to both shoulders and is associated with nausea and mild shortness of breath. He denies vomiting, dizziness or lightheadedness. He notes that he had an episode of similar pain yesterday afternoon which lasted about 20 minutes and then resolved spontaneously after he lay down. He has no known cardiac history.
Vital signs are normal. The physical exam is also normal.
An ECG is done
What is the most likely cause of the ECG findings in this patient?