The deceptive presentation: diagnosing stemi by serial ecg in a patient with dyspnea and sweating

Background: Prompt diagnosis of acute ST-elevation myocardial infarction (STEMI) is crucial, but atypical presentations can delay recognition. This case highlights a 60-year-old male smoker presenting with dyspnea and diaphoresis, in whom serial electrocardiograms (ECGs) were essential for diagnosis. The electrocardiogram (ECG) is a fundamental tool for the rapid diagnosis of acute myocardial infarction (AMI). However, the initial ECG in patients experiencing AMI can be non- diagnostic, posing a significant challenge for timely intervention. Subsequent serial ECG recording over a short period revealed the progressive development of characteristic ST- segment elevation, ultimately leading to the diagnosis of ST- elevation myocardial infarction (STEMI). We discuss the timing of ECG changes, the role of bedside echocardiography, the significance of initial negative troponin, the risk of being an "apparently healthy" older individual, the impact of smoking with non- diagnostic ECGs, the diagnostic accuracy of ER physician-performed echocardiography, and the criteria for urgent catheterization in non-STEMI presentations. Case Presentation: A 60-year-old male smoker with no known comorbidities presented to the emergency department (ED) at 02:50 am on March 20, 2025, with a one-hour history of sudden onset shortness of breath and diaphoresis. His initial 12-lead ECG (02:50 am) was unremarkable, and the baseline troponin T was negative. Patient was given Bipap support to overcome the respiratory distress. No calf pain and intermittent claudication history. At 03:00 am, the patient developed chest discomfort. A second ECG showed subtle changes. By 03:42 am, a third ECG revealed a marked ST- segment elevation ("tombstone" pattern) in the same leads. Patient was shifted to Cathlab urgently. He underwent successful percutaneous coronary intervention (PCI) but developed cardiogenic shock in the cardiac care unit (CCU) and died. Conclusion: This case emphasizes that STEMI can occur with atypical symptoms and a non- diagnostic initial ECG. Serial ECGs are vital in such presentations. We address critical questions regarding the timing of ECG changes, the role of bedside echocardiography, the interpretation of early negative troponin, the risk in "apparently healthy" older smokers, the significance of smoking with non-diagnostic ECGs, the accuracy of ER-performed echocardiography, and the need for urgent catheterization in evolving non-STEMI cases.