46 YO M without PMHx presents with burning chest pain. After eating three bananas today, he had some generalized itching with associated throat and chest tightness and one episode of emesis. The patient’s initial ECG is shown:

Computer interpretation: sinus bradycardia, ST elevation, probably early repolarization

Physician interpretation: bradycardia at 54 bpm, sinus rhythm, normal axis, normal intervals, tall T waves in lead V2 and V3, ?ST elevation in V1

Differential: Hyperkalemia, benign early repolarization, hyperacute T-waves, sinus bradycardia

Why this ECG?: Is this benign early repolarization (BER)? Is there widespread concave ST elevation more notable in the precordial leads? Is there notching at the J-point especially at V3/V4? Yes and Yes. So this must be BER? Well, looking at the T wave of lead V2 is a bit concerning because of the amplitude of it and how quickly it shoots upwards. That is a very tall T-wave which should make us now think of either one of two things, hyperkalemia or hyperacute T-waves. Hyperkalemia is a global heart problem and should have peaked T waves in more than just V2/V3. Lastly, If we look at AVR, that TWI is deep and very pointy which suggests some sort of ischemia.

What did we do next? Repeat the ECG and check the electrolytes!

The repeat ECG 40 minutes later shows:

Physician interpretation #2: Anterior STEMI with reciprocal changes in inferior leads.

The cardiac catheterization lab was activated. The patient had a 100% occlusion of the LAD that was successfully stented. The patient’s initial troponin was negative.

The Heart of the Matter:

Don’t trust the computer interpretation!
If you see tall T waves think hyperkalemia or hyperacute T waves! To quote Dr. Amal Mattu, if the T wave is so large that the QRS complex can fit inside, that may be an early sign of ischemia.
ECGs are simple snapshots in time. Repeat the ECG to catch the dynamic ischemic process!

Thanks to Dr. Stephen Cooper and Dr. Bobby Needleman for sharing this great case.

Written by Joshua Kim, DO

Chief Resident, Cook County Health

Twitter: @joshekim

Edited by Tarlan Hedayati, MD

Chair of Education, Department of Emergency Medicine, Cook County Health

Twitter: @HedayatiMD

Additional readings:

Benign Early repol reading: https://litfl.com/benign-early-repolarisation-ecg-library/

Benign early repol Dr. Smiths ECG blog: https://hqmeded-ecg.blogspot.com/2015/10/best-explanation-of-terminal-qrs.html

Hyperkalemia: https://litfl.com/hyperkalaemia-ecg-library/

ECG weekly Hyperacute T Waves: https://ecgweekly.com/2020/08/amal-mattus-ecg-case-of-the-week-aug-3-2020/