What ECG finding is indicative of an inferior STEMI?

An inferior STEMI, or ST-Elevation Myocardial Infarction, typically occurs as a result of occlusion in the right coronary artery (RCA) in a right-dominant coronary system, affecting the inferior portion of the heart. The key indicator for an inferior STEMI on an ECG is ST elevation in the specific leads that correspond to the inferior wall of the heart.

The leads that show ST elevation in an inferior STEMI are II, III, and aVF. These leads are positioned to monitor the inferior wall of the heart, which is supplied by the RCA. When there is a blockage in this artery, the resultant ischemia causes a characteristic ST elevation in these leads, marking the ECG changes associated with an inferior STEMI.

In contrast, other combinations of leads that show ST elevation or depression do not reflect the classic inferior wall involvement. For instance, ST elevation in leads I, II, and III could suggest a larger area of injury or different positioning than what is specifically associated with an inferior STEMI, while elevation in leads V1 and V2 points towards anterior wall issues, commonly relating to the left anterior descending artery. Meanwhile, ST depression in lead V3 does not indicate an inferior STEMI and can suggest ischem