EKG Challenge No. 13: "I feel much better now"

You are working one evening in the emergency department when you walk in to see your 4th chest pain patient of the night.  Your current patient is a 50-something year old male who's years of homelessness and cocaine abuse have made him appear older than his stated age.  He tells you that he he has been having left sided chest pain on and off for the last 3 hrs.  He received ASA and nitro x 2 in the ambulance and now feels much better.  You examine his EKG from today:

EKG #1 (day of presentation)

You then compare it to his EKG from two days ago when he came in for chronic diarrhea and chest pain, but was chest pain free at the time:

EKG #2 (EKG from two days prior to presentation)

... and compare it again with his EKG from 1 year before during an admission for chest pain in which he had a negative cardiac stress test:

EKG #3 (EKG from one year prior to presentation)

  

What is your differential?  What is your management and dispo plan? 

Read the Case Conclusion here.