• The inferior wall of the left ventricle is supplied by the posterior ascending artery (PDA) branch of either the right coronary artery (RCA) if right-dominant, left circumflex artery (LCx) if left-dominant, or both RCA and LCx if co-dominant. Rarely, it is supplied by the "wrap-around" LAD that curves around the apex reaching a far distance upward posteriorly.
• Electrical activity of the inferior wall is detected by the inferior leads (II, III, aVF).
• Patterns of inferior STEMI, corresponding ECG leads exhibiting ST elevation, and culprit lesion(s) are listed below:
Isolated inferior --- II, III, aVF --- PDA
Inferior-RV --- II, III, aVF + V1-2 + V3R-6R --- proximal RCA or RCA/left-dominant PDA
Inferoposterior --- II, III, aVF + V7-9 --- PDA
Inferolateral --- II, III, aVF + V5-6, aVL, I --- LCx/PDA or dominant LCx
Inferoposterolateral --- II, III, aVF + V7-9 + V5-6, aVL, I --- LCx/PDA or dominant LCx
Anteroinferior --- II, III, aVF + V2-4 --- mid-distal wrap-around LAD or distal LAD/PDA
• Isolated inferior MI is caused by an occlusion of the --
Posterior ascending artery (PDA) branch of the right coronary artery (RCA) if right-dominant, left circumflex artery (LCx) if left-dominant, or both RCA and LCx if co-dominant, or
Distal wrap-around left anterior descending artery (LAD)
• ECG findings associated with isolated inferior MI include:
ST elevation in inferior leads (II, III, aVF)
Reciprocal ST depression in lateral leads (I, aVL)
• On echocardiography, there is hypo/akinesis of the inferior wall (shaded in grey below) seen in apical 2 chamber and parasternal short axis views.
• Inferior-RV MI is caused by occlusion(s) of the --
Proximal dominant right coronary artery (RCA) and its branches including the posterior ascending artery (PDA),
Proximal non-dominant RCA and PDA of the dominant left circumflex artery (LCx), or
Proximal non-dominant RCA and distal wrap-around left anterior descending artery (LAD)
• ECG findings associated with inferior-RV MI include:
ST elevation in inferior (II, III, aVF) and right-sided (V1R-6R) leads
ST elevation in III greater than ST elevation in lead II
Reciprocal ST depression in lateral leads (I, aVL)
• On echocardiography, there are hypo/akineses of the inferior and RV free walls (shaded in grey below) seen in apical 4- and 2- chamber, and parasternal long and short axis views.
• Inferoposterior MI is caused by an occlusion of the --
Posterior ascending artery (PDA) branch of the right coronary artery (RCA) if right-dominant, left circumflex artery (LCx) if left-dominant, or both RCA and LCx if co-dominant.
• ECG findings associated with inferoposterior MI include:
ST elevation in inferior (II, III, aVF) and posterior V7-9) leads
Reciprocal ST depression with upright T wave in anteroseptal leads (V1-3)
Reciprocal ST depression in lateral leads (I, aVL)
• On echocardiography, there are hypo/akineses of the inferior and posterior walls (shaded in grey below) seen in apical 4 chamber, apical 2 chamber and parasternal short axis views.
• Inferolateral MI is caused by occlusion(s) of the --
Proximal dominant left circumflex artery (LCx) and its branches including the posterior descending artery (PDA), or
PDA branch of the dominant right coronary artery (RCA) (supplying the inferior wall) and the LCx (supplying the lateral wall)
• ECG findings associated with inferolateral MI include:
ST elevation in inferior (II, III, aVF) and lateral (I, aVL) leads
• On echocardiography, there are hypo/akineses of the inferior and lateral walls (shaded in grey below) seen in apical 4- and 2- chamber, and parasternal long and short axis views.
• Inferoposterolateral MI is an extension of inferolateral MI, caused by occlusion(s) of the --
Proximal dominant left circumflex artery (LCx) and its branches including the posterior descending artery (PDA), or
PDA branch of the dominant right coronary artery (RCA) (supplying the inferior and posterior walls) and the LCx (supplying the lateral wall)
• ECG findings associated with inferoposterolateral MI include:
ST elevation in inferior (II, III, aVF), posterior (V7-9), and lateral (I, aVL) leads
Reciprocal ST depression with upright T waves in anteroseptal leads (V1-3).
• On echocardiography, there are hypo/akineses of the inferior, posterior, and lateral walls (shaded in grey below) seen in apical 4- and 2- chamber, and parasternal long and short axis views.
• Anteroinferior MI is caused by occlusion(s) of the --
Mid-distal wrap-around left anterior descending artery (LAD), or
Mid-distal LAD (supplying the mid-anterior wall) and the posterior ascending artery (PDA) (supplying the inferior wall)
• ECG findings associated with anteroinferior MI include:
ST elevation in anterior (V2-6) and inferior (II, III, aVF) leads
Reciprocal ST depression in lateral leads (I, aVL)
• On echocardiography, there are hypo/akineses of the inferior and anterior walls (shaded in grey below) seen in apical 4- and 2- chamber, and parasternal long and short axis views.
