As always, the history is crucial. In an unwell patient, with other symptoms, or past cardiac history, assume any ST elevation is sinister, until proved otherwise.
However, if you've done an ECG purely to reassure an anxious patient, who is other wise fit and well, and you are convinced by the history and examination that this is non-cardiac; then think seriously about whether the changes you can see are simply high take-off.
Here are some common patterns of ST elevation, I have tried to highlight the main differences between them:
1. Antero-lateral STEMI - Localised, convex ST segments:
2. Pericarditis - Non-localised, scooped or saddleback ST changes, often notched:
3. Benign High Take-off - Often antero-lateral, but different shape form to STEMI. Often with notched J point seen in V4, and Tall T-waves:
4. Left Bundle Branch Block - The notable feature is the wide QRS complex. The ST segments and T wave changes are opposite (discordant) to the dominant QRS component (The T-wave and ST changes are in the same direction as each other). There is ST elevation pattern in V1-4 :
Hope this is helpful.
We'll look at each, more specifically, in a later ECG quizzes . So be warned, keep them in mind! ;)