A 55-year-old man is brought to the Emergency Department with ongoing severe central chest pain, described as crushing and radiating to his left arm, which started 1 hour ago. His 12-lead ECG shows 3mm ST segment elevation in leads II, III, and aVF, with reciprocal ST depression in leads I and aVL. Which coronary artery territory is most likely affected by the myocardial infarction?