This document discusses the challenges in differentiating between ST elevation myocardial infarction (STEMI) and pericarditis based on electrocardiogram (ECG) findings. While pericarditis is classically taught to present with diffuse ST elevation and PR segment depression, in reality the findings can be more localized. STEMI can also occasionally present with concave ST elevation. The document provides factors that favor STEMI over pericarditis, including ST depression beyond leads aVR and V1, convex or horizontal ST elevation, and greater ST elevation in lead III than II. It emphasizes getting serial ECGs when the diagnosis is unclear and discusses an example where PR depression occurred due to atrial injury in the setting of acute

1. ACUTE STEMI vs PERICARDITIS
ECG DILEMMA
Dr. Syed Haseeb Raza
FCPS Cardiology, Clinical Cardiac Electrophysiologist
Author of ECG Book and Researcher
National Institute of Cardiovascular Diseases, Karachi, Pakistan.
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2. 40 yr old male presenting with chest pain

3. What is your ECG
diagnosis?
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4. Answer will be disclosed at the end of presentation

5. Classical Teachings about Pericarditis
• Diffuse ST elevation in all leads
• ST elevation is concave upwards
• PR segment depression with PR elevation in lead aVR

6. ..
• Classic Teaching
• Diffuse ST elevation in all leads
In reality : may be localized instead of diffuse
Pearl : No ST segment depression except in leads aVR and V1
• ST elevation is concave upwards
Acute STEMI can also give such configuration.
Pearl : ST segment elevation that is convex upwards and horizontal
strongly favors STEMI
Another pearl : STE II > STE III favors Pericarditis
STE III > STE II favors STEMI
• PR segment depression with PR elevation in lead aVR
In reality : PR segment depression is an early transient finding
It also occurs in ACS ( when there is atrial injury )
So ,,,its NOT pathognomic for Pericarditis

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8. Factors strongly Favoring STEMI
• ST segment depression beyond aVR and V1
• ST segment elevation convex upwards or horizontal
• STE III > STE II

9. Factors strongly Favoring STEMI
• ST segment depression beyond aVR and V1
• ST segment elevation convex upwards or horizontal
• STE III > STE II
Factors strongly favoring Pericarditis
• Pronounced PR depression in multiple leads

10. Pericarditis vs STEMI
When indoubt get “serial ECGs”
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11. 1. STEMI or Pericarditis ?

12. Its infero lateral STEMI
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13. 2. STEMI or Pericarditis ?

14. Its anterolateral STEMI
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15. 3. STEMI or Pericarditis ?

16. Its PERICARDITIS
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17. 4. STEMI or Pericarditis ?

18. Note PR segment elevation in lead aVR
yet its STEMI ( ST elevation in anterolateral leads
, reciprocal ST depression in leads III , aVF)
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19. 5. STEMI or Pericarditis ?

20. The most marked finding in this ECG is PR depression in multiple leads
BUT question is
What is the reference for ST elevation or depression in the presence of PR
depression ???
“Its T-P segment”
So taking T-P segment as standard what is happening in lead III and V6 ??
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22. So its ACS ,,,,,,
why PR segment depression ?
Do not forget “ATRIAL INJURY”
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23. Coming back to the first slide of presentation.
STEMI or Pericarditis ?

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25. This patient had triple vessel disease
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26. Take Home Message
Step 1 : ST segment depression beyond aVR and V1
 if YES its STEMI  if NOT , move to next step 2
Step 2 : ST segment elevation convex upwards or horizontal
 if YES its STEMI if NOT, move to next step 3
Step 3 : STE III > STE II  if YES its STEMI
 if NOT, move to next step 4
Step 4 : Pronounced PR depression in multiple leads
 if YES its PERICARDITIS

27. STEMI vs Pericarditis
When indoubt get serial ECGs
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28. THANKYOU
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