From the Guidelines
STEMI mimics include conditions such as left ventricular hypertrophy, left bundle branch block, pericarditis, early repolarization, Brugada syndrome, Takotsubo cardiomyopathy, hyperkalemia, pulmonary embolism, and ventricular aneurysm, which can produce electrocardiogram (ECG) changes resembling ST-segment elevation myocardial infarction (STEMI) but are not caused by acute coronary artery occlusion.
Key Conditions
- Left ventricular hypertrophy
- Left bundle branch block
- Pericarditis
- Early repolarization
- Brugada syndrome
- Takotsubo cardiomyopathy
- Hyperkalemia
- Pulmonary embolism
- Ventricular aneurysm
These conditions can create ST-segment elevations or other ECG abnormalities that may be mistaken for a true STEMI, as noted in the 2021 European Heart Journal guidelines 1. Distinguishing these mimics from actual STEMI is crucial because treatment approaches differ significantly. For example, administering thrombolytics or performing emergency cardiac catheterization for a STEMI mimic could expose patients to unnecessary risks without benefit.
Diagnostic Approach
Clinicians should consider the entire clinical picture, including:
- Patient symptoms
- Medical history
- Physical examination findings
- Cardiac biomarkers
- Sometimes additional imaging like echocardiography to differentiate true STEMIs from mimics, as recommended by the 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction 1. The presence of reciprocal ST depression in leads opposite to those showing elevation often suggests true STEMI, while diffuse ST elevations with PR depression may indicate pericarditis. Understanding these distinctions helps prevent inappropriate interventions while ensuring patients receive proper treatment for their actual condition.
From the Research
STEMI Mimics
- Benign early repolarization, acute pericarditis, and left ventricular aneurysm are examples of STEMI mimics, as they can cause ST-segment elevation on an electrocardiogram (ECG) without being related to a coronary-based syndrome 2
- Other conditions that can mimic STEMI on ECG include Prinzmetal's angina, takotsubo cardiomyopathy, Brugada syndrome, hypothermia, and hyperkalemia 3
- Pulmonary embolism is a rare but potential STEMI mimic, presenting with abnormal EKG and biomarkers that may appear to be an acute coronary syndrome, even STEMI 3
Characteristics of STEMI Mimics
- STEMI mimics can present with ST-segment elevation and other electrocardiographic abnormalities similar to those found in STEMI 4
- A 12-lead ECG is crucial in diagnosing STEMI and differentiating it from STEMI mimics 2, 5
- Knowledge of ECG patterns that can mimic STEMI is essential for accurate diagnosis and decision-making in emergency medicine 5
Importance of Accurate Diagnosis
- Accurate diagnosis of STEMI and its mimics is critical to ensure prompt and appropriate treatment 2, 5
- Delayed diagnosis or misdiagnosis of STEMI mimics can lead to inappropriate therapy and adverse outcomes 3, 4
- A high index of clinical suspicion and risk stratification are necessary to identify STEMI mimics and provide appropriate treatment 3