Calvin is a 65-year-old Black man who has a 12-year history of Type II diabetes and a 40-year history of tobacco use. He has hypertension and high cholesterol, for which he is taking a beta blocker (Metoprolol), a cholesterol-lowering drug (Atorvastatin), and an oral diabetes medication (Metformin)Calvin presented at the ER with substernal pain radiating through his back and left arm . He is experiencing difficulty breathing, which is worse upon exertion, along with nausea and sweating. Calvin's blood pressure is 165/110 and his heart rate is 95 bpm. His oxygen saturation is 89 %, which is low. Lung sounds are normal with no wheezing or congestion. His temperature is slightly elevated at 99.1 . You suspect that Calvin is having a heart attack. What tissue layer of the heart is primarily being affected ?
A. Myocardium
B. Endocardium
C. Epicardium
D. Pericardium