A 29-year-old otherwise healthy male patient presents with sudden intense constricting retrosternal pain, along with dry cough and breathlessness at rest. He smokes and is a heavy drinker, but denies any recent trauma, use of any medications, previous surgeries or hospital admissions. His clinical condition progressively deteriorates and he is admitted to an emergency department few hours later. Chest radiography is performed.

Question:
Based on the clinical history and imaging herein presented, the most likely diagnosis is: