The electrocardiogram (ECG) is a critical tool of practicing physicians, including general internists, family medicine practitioners, intensivists, emergency physicians, cardiologists, and others. It is used to rapidly identify patients who require time-sensitive therapies such as emergent reperfusion therapy, as well as identify acute or chronic life-threatening conditions such as rhythm disorders, poisonings, electrolyte disturbances, or predisposition to sudden death. We are pleased to launch, in this issue of the Archives, a new section dedicated to the ECG titled “Challenges in Clinical Electrocardiography.”