What is a hallmarked ECG feature of STEMI?

ST segment elevation is a hallmark characteristic of ST-Elevation Myocardial Infarction (STEMI) on an electrocardiogram (ECG). This elevation occurs due to the complete occlusion of a coronary artery, leading to significant ischemia and injury to the heart muscle. When there is a loss of blood flow, the affected myocardial tissue cannot repolarize properly, which manifests as an elevated ST segment in the leads corresponding to the area of the heart that is ischemic.

In the context of diagnosing a STEMI, ST segment elevation is typically greater than 1 mm in limb leads or greater than 2 mm in precordial leads. This distinctive feature helps clinicians quickly identify STEMI, facilitating timely intervention to restore blood flow and minimize cardiac damage. Other ECG changes, such as T wave inversion or flat T waves, may indicate other conditions but are not definitive for STEMI. ST segment depression may suggest ischemia but does not indicate the acute injury associated with STEMI. Thus, the presence of ST segment elevation is a critical marker that guides both diagnosis and management in acute coronary syndrome scenarios.