Why EMS captures a 12-lead ECG with the first set of vital signs

Too often, paramedics think of the 12-lead ECG as just one of the things to check off the list

EMS is called to the residence of a 66-year-old female complaining of chest discomfort. The patient is found sitting in a kitchen chair. She is alert and oriented but highly anxious and diaphoretic. She appears acutely ill.

Paramedics assess her vital signs.

  • Respiratory rate: 18
  • Pulse: 74
  • NIBP: 102/63
  • SpO2: 95

A 12-lead ECG is obtained.

Although this ECG meets the voltage criteria for left ventricular hypertrophy in the limb leads, it shows acute inferior STEMI.

ST-elevation is present in leads II, III and aVF along with reciprocal ST-depression in leads I and aVL. Remember that left ventricular hypertrophy is usually an anterior STEMI mimic.

A "Code STEMI" was called from the field. The patient was given four baby aspirin, a sublingual nitroglycerin spray and oxygen.

Less than four minutes later, the patient was in the back of the ambulance and another 12-lead ECG was captured.

As you can see, the ECG is now nondiagnostic for acute STEMI. This patient's reperfusion could have been seriously delayed. But, because the paramedics obtained a 12-lead ECG with the first set of vital signs, the patient was taken rapidly to the cardiac catheterization lab, where an acute 99 percent occlusion of the right coronary artery (RCA) was identified and stented.

The patient's door-to-balloon time was less than 60 minutes.

Too often, paramedics think of the 12-lead ECG as just one of the things to check off the list. "I need to place the patient on oxygen, I need to start an IV, I need to give baby aspirin, I need to give nitroglycerin, I need to get a 12-lead ECG…"

In reality, early acquisition of a 12-lead ECG for all patients with signs and symptoms of ACS is critically important to the success of a prehospital 12-lead ECG program.

Why? Because the same drugs we give to restore balance between myocardial oxygen supply and demand can "clean up" or erase ischemic changes on the 12-lead ECG.

Sometimes the prehospital 12-lead ECG is the only evidence that a patient's chest pain was cardiac in origin! Imagine if this patient never received a prehospital 12-lead ECG and the cardiac biomarkers came back negative.

A patient with a high-risk lesion might have been discharged home. It's unlikely, but it could happen. What would you want for your mother or father?

Read next about the importance of performing serial ECGs.

About the author

Tom Bouthillet is a Fire Captain/Paramedic with Hilton Head Island Fire & Rescue, Editor-in-Chief of the EMS12Lead.com, Chief Content Architect of ECGMedicalTraining.com, host of the Code STEMI web series at First Responders Network, a member of the Editoral Advisory Board of EMS World Magazine, and developer of the 12-Lead ECG Challenge smartphone app. He has taught nationally in the Critical Care Transport (CCEMT-P) program out of UMBC and his writings have been referenced in the American Heart Journal, the Journal of the American College of Cardiology: Cardiovascular Interventions and the EP Lab Digest. Contact Tom at tom.bouthillet@ems1.com.

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