A 62-year-old woman was brought into the admission room with complaints of severe burning retrosternal pain and asphyxia. She has a 10-year-long history of essential hypertension. Objectively her condition is moderately severe. She presents with skin pallor, cyanotic lips, and vesicular respiration over her lungs. The II heart sound is accentuated over the aorta. Blood pressure — 210/120 mmHg, heart rate (pulse) — 76/min. ECG shows elevation of ST segment in the leads I, aVL, and V5-V6. What is the most likely diagnosis?