The diagnosis of acute myocardial infarction (AMI) is undergoing a significant transformation. For decades, classifying AMI as with or without ST-segment elevation (STEMI and NSTEMI) guided clinical practice, focusing on the presence or absence of this electrocardiographic marker as the main criterion for therapeutic decisions. However, new evidence points to the limitations of this approach, especially in accurately identifying coronary occlusions that require urgent intervention.

The Evolution of the Paradigm: From Q-Wave and Non-Q-Wave Infarction to OMI/NOMI

Historically, the diagnosis of AMI was based on the presence of Q waves on the electrocardiogram (ECG), classifying infarctions as Q-wave or non-Q-wave. With the advance of reperfusion therapies, the focus shifted to identifying ST-segment elevation, creating the STEMI and NSTEMI paradigms. Although this approach was a significant advance, it underestimates the complexity of acute coronary syndromes.

Today, the paradigm is evolving again with the introduction of the concepts of occlusion myocardial infarction (OMI) and non-occlusion myocardial infarction (NOMI). This new model offers a more accurate and comprehensive basis for diagnosing and managing AMI, taking into account not only the ST segment but also other electrocardiographic criteria and additional tests.

The phrase “paradigm shift” written in chalk on a blackboard next to a stopwatch

The Sensitivity of ST-Segment Elevation

Although ST-segment elevation is the most important electrocardiographic sign of acute coronary occlusion, in a comprehensive meta-analysis performed by our team we found that up to 50% of acute coronary occlusions do not show classic ST-segment elevation. This means that many patients with OMI may not be identified in time, resulting in critical treatment delays.

Electrocardiographic Signs of Acute Coronary Occlusion

In the setting of OMI, the ECG remains an essential tool, but accurate interpretation goes beyond the ST segment alone. Some of the electrocardiographic signs that indicate possible OMI include:

Conclusion

This new approach not only refines the diagnosis of AMI, but also highlights the importance of timely intervention. The OMI/NOMI paradigm opens the door to new research and clinical practices, especially in a context where accuracy and individualized treatment are increasingly valued. It also draws attention to the crucial role of physicians in interpreting signs beyond the conventional, ensuring that no patient with coronary occlusion is overlooked.

References

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