Final answer:
ST-segment deviations include elevation, indicating acute myocardial infarction, depression, typically from hypoxia, and normalization which takes place when the ST-segment returns to the baseline after deviation.
Step-by-step explanation:
ST-segment deviations on an electrocardiogram (ECG) can indicate various forms of heart pathologies. The three classifications of ST-segment deviation include elevation, depression, and normalization. ST-segment elevation is often seen in patients with an acute myocardial infarction (MI). ST-segment depression is typically associated with conditions such as hypoxia. Importantly, both conditions require thorough clinical evaluation as they may signal critical cardiac issues.