The No False Negative Paradox in MI Diagnosis

In the diagnosis of acute myocardial infarction (MI), the distinction between ST-elevation MI (STEMI) and non-ST-elevation MI (NSTEMI) has always been fundamental in guiding therapeutic decisions. However, the article by de Alencar et al. (2024) introduces an innovative discussion of the “no false negative paradox” in the diagnosis of STEMI. Let's explore how this concept challenges current clinical practice and its impact on the management of acute coronary occlusion (OMI).

The No False Negative Paradox

The diagnosis of STEMI is based on the presence of ST-segment elevation in at least two contiguous leads on the electrocardiogram (ECG). However, the absence of ST elevation does not necessarily rule out OMI, leading to a diagnosis of NSTEMI even when the underlying pathophysiology is similar to that of STEMI. This phenomenon is called the “no false negative paradox” because patients without ST elevation may not be recognized as having a condition that would benefit from immediate reperfusion, resulting in treatment delays.

Incorporation Bias

One of the factors contributing to this paradox is incorporation bias, in which the diagnostic test (ST elevation on the ECG) is part of the very definition of the disease (STEMI). This makes the sensitivity of the test appear to be 100%, since ST elevation is mandatory for the diagnosis. However, more than 50% of patients with OMI do not show ST elevation, as shown in recent meta-analyses, which demonstrates that many OMI cases are misclassified as NSTEMI when in fact they could benefit from rapid interventions, such as angioplasty.

Feedback Bias

Another possible bias is feedback bias, which occurs when healthcare professionals do not receive feedback on cases in which the diagnosis of NSTEMI was incorrect because of an undetected OMI. Since these patients are labeled as NSTEMI even after an OMI is discovered during hospitalization, diagnostic errors go unnoticed, preventing professionals from improving their diagnostic processes. This cycle of missed learning perpetuates the problem and hinders the evolution of clinical practice.

Cognitive Comfort and Resistance to Change

The article also discusses the concept of “cognitive comfort”, in which healthcare professionals settle into the familiarity of the existing literature that validates the STEMI-NSTEMI paradigm. This comfort makes it harder to adopt new paradigms that better represent the pathophysiology of the disease, such as the concept of OMI without ST elevation. This attachment to the traditional paradigm results in resistance to innovation and to critical reconsideration of the diagnostic criteria.

Conclusion

The discussion around the “no false negative paradox” in STEMI-NSTEMI diagnosis reveals an urgent need to rethink the criteria we use to diagnose MI. It is essential that physicians be aware of the limitations of ST-elevation-based criteria and seek approaches that recognize OMI in patients with NSTEMI, offering them appropriate and timely treatment. By challenging the status quo, we can move toward more accurate diagnoses and, consequently, better patient outcomes.