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EKG December 2018




Paramedics respond to a 68-year-old female presenting with weakness and chest pressure.  She states she “just feels bad” and her chest feels heavy. The symptoms started 45 minutes ago when she was doing laundry.  She sat down because of the discomfort but it would not go away.  She has a past medical history of hypertension and diabetes mellitus.  The patient appears to be in distress.

Case presentation



What is your interpretation of this ECG?

Rate:                                       90 bpm                                   

Rhythm:                                  Sinus Rhythm – there are p waves before each QRS

ST Segment Elevation >1mm

In 2 or more contiguous

Leads?:                                    No 

Reciprocal Changes:              N/A                 

Other Abnormalities:                        There are tall, prominent, t waves in V2-V4.


Learn more about this ECG pattern

This ECG and patient history are concerning for acute coronary syndrome.  The ECG demonstrates ‘hyperacute’ t-waves which can be an early sign of an evolving STEMI.  Coronary artery occlusion typically leads to ST elevation, but changes in t-wave shape and amplitude may be an earlier finding.  As compared to the peaked t-waves seen in hyperkalemia, hyperacute t-waves in myocardial infarction are localized to the region of infarct and typically have a broad base.  Hyperkalemic t-waves are diffuse and typically narrow-based with a sharp “peak” at the apex.

Figure 1: This ECG demonstrates peaked t-waves that are consistent with hyperkalemia


How would you manage this patient?

This patient is having cardiac chest pain due to an anterior myocardial infarction from a left anterior descending (LAD) coronary artery occlusion even though ST elevations are not yet apparent.  Treatment should be in accordance with TP 1211 “Cardiac Chest Pain”.  Initial provider impression would be Chest Pain Suspected Cardiac.  However, the ECG should be repeated since her presentation and past medical history put her at high risk for myocardial infarction and there should be a high clinical suspicion for an evolving STEMI.  It is appropriate to discuss destination with the Base hospital given this concern.

A repeat ECG is shown below:

Figure 2.  A repeat ECG demonstrates an evolving antero-lateral STEMI.  Note the ST elevations now present in V1-V6.  There is reciprocal ST depression in leads III, aVF and ST elevation in leads I and aVL, a sign of developing lateral involvement. 


The provider impression is now Chest Pain STEMI.  Initiate ECG transmission and notify the closest STEMI Receiving Center (SRC) as soon as STEMI is identified in accordance with MCG 1303.  Transport the patient to the closest SRC. 


1. Levis JT. ECG Diagnosis: Hyperacute T Waves. Perm J. 2015;19(3):79.

2. Nable JV, Brady W. The evolution of electrocardiographic changes in ST-segment elevation myocardial infarction. Am J Emerg Med. 2009 Jul;27(6):734–46.