stillnotcharlie

I would love the wisdom of the educated crowd on this one. I am not an EMT. Just interested in understanding how an EMT or Paramedic would approach this hypothetical: A 70 year old man collapses in a hotel lobby after having chest pain. By the time EMS is there, he is unresponsive and likely having a massive heart attack. Do you ever give nitro in this situation? How do you know if there are contraindications like ED meds? Assuming nitro is something you would give, what happens if the patient was on ED meds and was given nitro as well?