What is a characteristic feature of STEMI on an ECG?

The characteristic feature of STEMI (ST-Elevation Myocardial Infarction) on an ECG is the elevation of the ST segment. This elevation indicates that there is a complete blockage of a coronary artery, resulting in damage to the myocardial tissue. The ST segment elevation appears as a notable upward deflection in the ECG tracing, which is critical for diagnosing a STEMI. The presence of ST segment elevation often signifies ongoing injury to the heart, prompting immediate medical intervention to restore blood flow and minimize damage.

In contrast, the other options represent different conditions or findings on an ECG that do not specifically indicate a STEMI. For example, T wave depression can indicate ischemia but is not diagnostic of STEMI. Arrhythmias without ST changes can occur in various cardiac conditions and do not provide the specific indication of myocardial infarction that ST elevation does. Finally, a normal ECG showing no change typically rules out any acute ischemic event like STEMI. Thus, the elevation of the ST segment is a definitive marker that guides healthcare providers in timely decision-making during acute myocardial infarction scenarios.