Acute Myocardial Infraction ECG features

NEET PG
#1

Acute Myocardial Infraction ECG features

  1. ST segment elevation in the anterior leads (V3 and V4) at the J point and sometimes in the septal or lateral leads, depending on the extent of the MI.

  2. This ST segment elevation is concave downward and frequently overwhelms the T wave.

! Lateral STEMI ECG features:

  1. ST elevation in the lateral leads (I, aVL, V5-6).

  2. Reciprocal ST depression in the inferior leads (III and aVF).

  3. ST elevation primarily localised to leads I and aVL is referred to as a high lateral STEMI.

***Note: Reciprocal change in the inferior leads is only seen when there is ST elevation in leads I and aVL. This reciprocal change may be obliterated when there is concomitant inferior ST elevation (i.e an inferolateral STEMI).

! Inferior STEMI ECG features:

***RCA occlusion is suggested by:

  1. ST elevation in lead III > lead II.

  2. Presence of reciprocal ST depression in lead I.

  3. Signs of right ventricular infarction: STE in V1 and V4R.

***Circumflex occlusion is suggested by:

  1. ST elevation in lead II = lead III.

2)Absence of reciprocal ST depression in lead I.

  1. Signs of lateral infarction: ST elevation in the lateral leads I and aVL or V5-6.

***Note: Relative Q-wave depth in leads II and III is not useful in determining the culprit artery. Both RCA and LCx occlusion produce a similar pattern of Q wave changes, often with deeper Q waves seen in lead III.

▶️Non STEMI ECG features:

If there is elevation of the blood markers suggesting heart damage, but no ST elevation seen on the EKG tracing, this is known as a NSTEMI. NSTEMI may be associated with other EKG changes such as ST segment depression. Often looking at the EKG helps us to locate the area of the heart that is affected.