Where is the MI on ECG?
Where is the MI on ECG?
ECG Changes during Myocardial Infarction (MI)
| Location of MI | Leads Affected | ECG Changes |
|---|---|---|
| Lateral wall | I, aVL, V5, V6 | ST-segment elevation |
| Inferior wall | II, III, aVF | T-wave inversion ST-segment elevation |
| Posterior wall | V1 to V4 | Tall R waves ST-segment depression Upright T waves |
What is the most common location of MI?
The vast majority of MI involves the anterior wall (78%). The most common coronary artery affected is the left anterior descending (LAD) branch. Coronary dissection is the primary cause of infarction in the peripartum period and more commonly in the postpartum period.
Which leads show which MI?
Right-sided chest leads are necessary to recognize RV MI. In general, the more leads of the 12-lead ECG with MI changes (Q waves and ST elevation), the larger the infarct size and the worse the prognosis. Additional leads on the back, V7-9 (horizontal to V6), may be used to improve the recognition of true posterior MI.
Why is ST segment elevation in myocardial infarction?
ST-segment elevation usually indicates a total blockage of the involved coronary artery and that the heart muscle is currently dying. Non-STEMI heart attacks usually involve an artery with partial blockage, which usually does not cause as much heart muscle damage.
When do you check for posterior MI?
In patients presenting with ischaemic symptoms, horizontal ST depression in the anteroseptal leads (V1-3) should raise the suspicion of posterior MI. Posterior infarction is confirmed by the presence of ST elevation and Q waves in the posterior leads (V7-9).
Which leads show posterior wall MI?
The ECG findings of an acute posterior wall MI include the following: ST segment depression (not elevation) in the septal and anterior precordial leads (V1-V4). This occurs because these ECG leads will see the MI backwards; the leads are placed anteriorly, but the myocardial injury is posterior.
Which leads show anterior MI?
The ECG findings of an acute anterior myocardial infarction wall include: 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. This ST segment elevation is concave downward and frequently overwhelms the T wave.
What is the difference between ST elevation and ST depression?
According to the theory of the ischemie injury current there is a noticeable ST deviation in ECG of ischemie patient. ST depression has major role in detecting of ischemia. ST elevation is associated to special cases of ischemia or situation after myocardial infarction.
How do you tell if a STEMI is anterior or posterior?
Main ECG pointers for Posterior STEMI:
- Look for deep (>2mm) and horizontal ST-segment depression in the anterior leads and large anterior R-waves (bigger than the S-wave in V2).
- Posterior STEMI often occurs along with an inferior or lateral STEMI, but can also occur in isolation.
