The electrocardiogram (ECG) is an essential tool in cardiovascular diagnosis, including the interpretation of ventricular repolarization as depicted by ST-T wave changes. While these changes have traditionally been predominantly associated with myocardial ischemia, this narrow focus overlooks a wide range of non-ischemic conditions that can also influence ST-T segments, potentially leading to misdiagnosis and oversimplification in clinical practice. This manuscript reviews repolarization abnormalities through the established framework of primary and secondary repolarization changes [1]. Primary and secondary repolarization abnormalities are discussed, and this knowledge enables us to systematize diagnostic hypotheses for repolarization abnormalities in a patient-centered diagnostic process that transcends the conventional ischemia-centric model.