The most widespread presenting ailments among patients visiting the emergency department are chest pain and shortness of breath. These symptoms lead any doctor to a probable diagnosis of myocardial infarction (MI). Detailed patient history, testing of blood samples for cardiac biomarkers that are indicative of cardiovascular necrosis, ultrasound methods, electrocardiography, and coronary computed tomography (CT) could all be beneficial to support the diagnosis. Out of these, electrocardiography is the most important and commonly done investigation in the emergency departments for patients presenting with chest pain and shortness of breath. However, interpreting these patients' electrocardiograms (ECGs) may be a matter of concern and worry. T wave and ST-segment changes are often of interest in the early signs of myocardial ischemia. Despite its incredible sensitivity, ST-segment deviation (elevated or depressed) has a low specificity because it can be seen in a variety of other cardiac and non-cardiac diseases. When ST-segment anomalies are identified, clinicians must consider many additional characteristics (such as risk factors, symptoms, and anamnesis), as well as all other possible diagnoses.All of these scenarios of patients presenting in the emergency department with chest discomfort and shortness of breath showing ST-segment abnormalities can leave a healthcare professional wondering whether to start treatment for acute myocardial infarction, through either the administration of a fibrinolytic agent, exposing patients to both the benefits and risks of fibrinolysis, or invasive coronary angiography. An astute physician may be able to recognize fabricated differential diagnosis mimicking STsegment elevation myocardial infarction (STEMI) in some situations. Failure to recognize these imposters can result in inefficient resource utilization, which can expose patients to unjustified risk and increased rather than decreased death and morbidity. Since the danger of cerebral hemorrhage from blood thinners is significant, in patient-care scenarios, in order to rule out percutaneous coronary intervention (PCI), a thorough assessment of the ECG is essential to consider diseases other than acute myocardial infarction, especially the ones that are non-cardiac in origin. The goal of this narrative review is to give an overview of the significant disorders that are non-cardiac in origin that can mimic an ST-segment elevation myocardial infarction (STEMI).