I'm coming at this as someone who had an MI at a relatively young age:

For the goals -- and this may differ between EMT / paramedic & protocols -- but I would really wish that there was a blood draw done in the field. Before they bring you to the cath lab with a suspected MI, the ER is likely going to draw blood to get troponin levels at a 2-hour interval. You could save some time & heart muscle by getting a blood sample (containing initial levels) in the field.