A 54-year-old patient with fever treated in primary care and subsequently in an emergency department.54-year-old patient with history of hypertension treated with ramipril 10 mg/day. Smokes 20 cigarettes per day. Patient visits the emergency department with a fever of 38 degrees. He explains that four days earlier he experienced chest pain radiating to his back and shortness of breath. The following day he had a fever of 38.5 degrees and felt nauseous. He visited his primary care center, where he was diagnosed with a viral infection and prescribed paracetamol. In the emergency room, a fever of 38.4°C, blood pressure of 112/60 mmHg, and SpO2 of 96% are observed. Physical examination reveals no abnormalities. Laboratory tests are requested: C-reactive protein (18 mg/dL – normal value <0.5 mg/dL) and troponins (9780 pg/mL – normal value <45 pg/mL). The chest X-ray shows no abnormalities. Echocardiography showed global hypokinesia with a depressed ejection fraction (20%).Hospital admission is decided, and as per protocol, an electrocardiogram is performed, showing ST segment elevation of 2 mm in leads DI, DII, and aVF. The on-call cardiology department at the referral hospital is contacted, and it is decided to activate the heart attack protocol in order to perform emergency cardiac catheterization for angioplasty. The result is acute obstruction of the right coronary artery by 90% with placement of two drug-eluting stents.An appropriate protocol should be followed for patients who at any time present with chest pain, i.e., performing an electrocardiogram.Patients with fever, chest pain, and elevated myocardial enzymes, with decreased ejection fraction, are usually consistent with myopericarditis. In this case, the symptoms and findings pointed to that diagnosis, but the electrocardiogram findings led us to consider a more urgent condition, such as acute myocardial infarction.  In this case, the fever acted as a distracting factor, since the initial focus was on finding something infectious. The request for troponin testing was incidental, based on chest pain that had occurred four days earlier.Electrocardiogram should be requested immediately for all patients with chest pain. Patients are dynamic, and the therapeutic approach can be modified according to findings.