Unusual electrocardiographic signs in the emergency department: A narrative review

The electrocardiogram (ECG) remains an indispensable tool across clinical settings, routinely interpreted by physicians to evaluate acute symptoms, manage chronic conditions, and perform cardiovascular screening. Although common ECG patterns are readily recognized, less common or atypical findings can be challenging to identify despite their clinical significance, even for experienced clinicians. Familiarity with these distinctive patterns can improve and expedite clinical decision-making, particularly in time-sensitive diagnostic dilemmas, by facilitating the evaluation of both cardiac and non-cardiac conditions. Early recognition may enable timely, targeted treatment and guide further diagnostic evaluation. This manuscript highlights unusual electrocardiographic signs, focusing on their clinical relevance, underlying pathophysiology, and practical implications.