12-Lead on First Contact

Why do a 12-lead on first patient contact?

If your patient is having a STEMI, you can recognize it sooner and then immediately notify the ED to get the cath lab activated. This will save heart muscle that will lead to a better quality of life for your patient.

Why else should you do a 12-lead on first medical contact?

Here’s a clue:

Check out these three 12-leads and note their times:




The first ECG was done at 13:09. The 2nd was 13:17. The 3rd at 13:18.

While studies have shown that between 15-20% of STEMIs don’t emerge until the 2nd or 3rd ECG, there are also cases like the above where the STEMI disappears after the first ECG.

The patient above had an occluded right coronary artery. As his chest pain eased, his ST segment came down to the point it was gone by hospital arrival. Based on the prehospital ECG, the cath lab had already beeen activated and the patient was brought to the lab, where the chest pain and ST elevation returned, and then resolved when the clot ( a 99% occlusion) was cleared.

Life Pack monitors are equipped to track the ST segment. Here on the trend summary, you can see evidence of the ST segment coming back to normal.


Note: the second and 3rd ECG were automatically printed out by the Life Pack 12 due to the changing ST baseline in lead III, a feature of the LifePack monitors, which monitors the ST segment every thirty seconds and alerts you (by printing out a new 12-lead) when it records significant change.

Failure to do a 12-lead on first medical contact, particularly when the patient is having chest pain can lead to a missed or significantly delayed STEMI identification.

Do a 12-lead on first medical contact of all patients you suspect of Acute Coronary Syndrome. Do another 12-lead when you begin transport and a final on hospital arrival.


A recent study in Prehospital Emergency Care, A Prospective Evaluation of the Utility of the Prehospital 12-lead Electrocardiogram to Change Patient Management in the Emergency Department showed that nearly 20% of the prehospital ECGs in the study had significant abnormalities from the first ED ECG and that these abnormalities influenced the resulting care by the ED MD.

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