A posterior wall MI occurs when posterior myocardial tissue (now termed inferobasilar), usually supplied by the posterior descending artery — a branch of the right coronary artery in 80% of individuals — acutely loses blood supply due to intracoronary thrombosis in that vessel.
What coronary artery is affected in posterior MI?
Posterior myocardial infarction occurs when the posterior coronary circulation becomes disrupted. The two main branches of the coronary circulation are the right coronary artery and the left main coronary artery.
Which artery is occluded in MI?
Occlusion of the right coronary artery (RCA) may cause infarction of the inferior wall of the left ventricle with or without right ventricular (RV) myocardial infarction (MI), manifested as ST-segment elevations in leads II, III, and aVF.
Is posterior MI serious?
Clinical Significance of Posterior MI Posterior extension of an inferior or lateral infarct implies a much larger area of myocardial damage, with an increased risk of left ventricular dysfunction and death. Isolated posterior infarction is an indication for emergent coronary reperfusion.
What is posterior wall of heart?
The posterior aspect of heart contains essentially the venous channels and the atrium (LA in particular)pulmonary veins and coronary sinus. This happens right from 8 week heart open stage when venous end of lower straight heart tube folds up and posteriorly .
How is anterior wall MI diagnosed?
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.
- Reciprocal ST segment depression in the inferior leads (II, III and aVF).
What are the expected ECG changes in transmural myocardial infarction of the posterior wall?
In a myocardial infarction transmural ischemia develops. In the first hours and days after the onset of a myocardial infarction, several changes can be observed on the ECG. First, large peaked T waves (or hyperacute T waves), then ST elevation, then negative T waves and finally pathologic Q waves develop.
What is MI occlusion?
Background: Occlusion myocardial infarction (OMI) is defined as acute coronary occlusion or near occlusion with insufficient collateral circulation leading to downstream myocardial infarction.
What arteries of the heart are most commonly occluded?
The LAD artery is the most commonly occluded of the coronary arteries. It provides the major blood supply to the interventricular septum, and thus bundle branches of the conducting system.
How do you test for posterior stemi?
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.
What is the most posterior part of the heart?
The left atrium is the most posterior cardiac chamber being directly anterior to the oesophagus at the bifurcation of the trachea.
What are the most common complications seen with an anterior wall MI?
Complications
- Cardiogenic shock: Cardiogenic shock complicating anterior MI is associated with higher hospital mortality when compared to inferior MI.[21]
- Left ventricular dysfunction.
- Left ventricular mural thrombus.
- Ventricular septal rupture.
- Free wall rupture.
- Pericardial effusion from free wall rupture.
What is a posterior wall myocardial infarction?
Posterior Wall Myocardial Infarction (MI) ECG Review. The ECG findings of a posterior wall myocardial infarction are different than the typical ST segment elevation seen in other myocardial infarctions. A posterior wall MI occurs when posterior myocardial tissue (now termed inferobasilar), usually supplied by the posterior descending artery —…
What is the clinical significance of posterior MI?
Clinical Significance of Posterior MI. Isolated posterior infarction is an indication for emergent coronary reperfusion. However, the lack of obvious ST elevation in this condition means that the diagnosis is often missed. Be vigilant for evidence of posterior MI in any patient with an inferior or lateral STEMI.
What does posterior wall mi mean on ECG?
Posterior Wall Myocardial Infarction (MI) ECG Review. This occurs because these ECG leads will see the MI backwards; the leads are placed anteriorly, but the myocardial injury is posterior. A R/S wave ratio greater than 1 in leads V1 or V2. ST elevation in the posterior leads of a posterior ECG (leads V7-V9).
What is the difference between anterior wall ischemia and posterior wall mi?
Therefore ST-depression in the anterior leads may be confused for anterior wall ischemia, and a posterior STEMI might not be recognized. Posterior wall MI is most commonly associated with an inferior or lateral STEMI (occurring 15-20% percent of the time).
