A 46-year-old male presented with sudden onset of chest pain radiating to the left arm and shortness of breath. He has risk factors of smoking but no other medical history. On examination, his vitals were stable and heart and lung sounds were normal. The document discusses the arterial supply of the heart and how electrocardiogram leads correspond to different areas of the heart muscle. It provides detailed descriptions of ST segment changes that would indicate occlusions or blocks in different coronary arteries and the regions of the heart affected.

1. LOCALIZATION OF
MYOCARDIAL INFARCTION
UNIT 2
CHIEF
DR. D.SOJI MD GEN MED
PRESENTER
Rajamuthukrishnan PG

2.  A 46 Years old male presented with complaints of sudden onset of chest pain which
is retrosternal, compressive type radiating to left side of the chest and left arm for
the past 1 hour
 C/o shortness of breath present
 C/o excessive sweating present
 C/o dizziness
 No other complaints
 Not a k/c/o DM,HTN,CAD,CKD,TB,BA,Epilepsy,other illness
 Chronic smoker
 Vitals – PR- 70/Mt BP- 114/70 mm of Hg Spo2- 96% in RA
 CVS-s1s2 heard, no murmur
 RS- bilateral air entry present, no added sounds
 Abdomen- soft, no organomegaly
 CNS- NFND

4. What next?

6. Arterial supply of the heart
 Heart receives its blood supply from coronary arteries.
 Right coronary artery
 Left main coronary artery –
Left anterior descending artery
left circumflex artery

7.  Left anterior descending artery
Supplies the most of the anterior, anteroseptal and anterolateral wall of the
left ventricle (leads v1 – v6, Lead 1,aVL)
 Left Circumflex artery
Supplies the anterolateral (leads v5,v6,lead1,aVL) and posterolateral (lead
v7,v8,v9) wall of left ventricle
In 10-15% population it supplies the inferior wall (leads 2,3,aVF)
 Right coronary artery
Supplies the inferior wall (lead 2,3,aVF) and often posterolateral wall (lead
v7,v8,v9) of left ventricle
Only artery supplies the right ventricle( leads v3R-v6R)

8. ECG leads representation on heart
 Lead v1,v2 – ventricular septum
 Lead v2-v4 – anterior wall of the left ventricle
 Lead v5,v6,1,aVL - lateral wall of the left ventricle
 Lead 2,3,aVF – inferior wall of left ventricle
 Lead v7-v9 (special leads) – posterolateral wall of left ventricle
 Lead v3R-v6R (special right pre cordial leads) – right ventricle

9. Analysis of chest pain

10. Acute coronary syndrome
 Myocardial infarction with ST segment elevation(STEMI)
 Non ST segment elevation acute coronary syndrome
NSTEMI
Unstable angina

11. STEMI evolution
 ECG signs
Hyperacute T wave(Minutes - hours)
ST segment elevation(minutes – hours)
Pathologic Q wave (myocardial necrosis)(hours – days)

12. Left anterior descending artery
 Proximal occlusion
 First diagonal branch
 First septal branch
 Distal occlusion

13. Proximal occlusion of LAD – Extensive Anterior
wall MI
 ST elevation lead v1- v6,aVL , lead 1
 Reciprocal ST depression In lead 3,aVF

14. LAD occlusion – first diagonal branch
high lateral wall MI
 ST elevation in lead 1,Avl
 Reciprocal ST depression in lead 3,aVF

15. LAD occlusion – distal to first diagonal
branch(Proximal to first septal)
 ST elevation in lead v1-V4
 New onset RBBB

16. LAD occlusion – distal to first diagonal &
first septal branch (Apical MI)
 ST elevation in lead v2-v4 but not lead v1

17. LAD Wrap around occlusion
 ST elevation & Q wave in lead 2,3,Avf in addition to lead V2-V4

18. Left circumflex artery occlusion –
anterolateral MI
 ST segment elevation in lead v5,v6,lead1,Avl
 Reciprocal ST depression in Lead 3,aVF

19. Left circumflex artery occlusion –
posterolateral MI
 ST depression with tall R wave in lead v1-v3
 ST elevation in lead v5,v6
 ST elevation in posterior leads(v7-v9)

20. Left circumflex artery occlusion vs right
coronary artery occlusion
 Inferior wall MI due to left circumflex artery occlusion
ST elevation in lead 2,3 avF (Lead 2 > lead 3)
ST Segment isoelectric or elevated in lead 1,Avl
Reciprocal ST depression in lead v2,v3
 Inferior wall MI due to right coronary artery occlusion
ST segment elevation in lead 3 > lead 2
Reciprocal ST depression in lead Avl > lead 1
Features suggestive of Right ventricle MI(Proximal RCA occlusion) like ST
elevation in lead v1, V3r – v6R, AV nodal block

21. Right coronary artery occlusion- inferior
wall MI
 ST elevation in lead 2,lead 3,Avf
 Reciprocal ST depression in lead 1,Avl

22. Right coronary artery- inferolateral wall MI
 ST elevation in lead 2,lead 3,Avf with ST elevation in lead v5,v6

23. Right coronary artery occlusion –
inferoposterior wall MI
 ST elevation in lead 2, lead 3, Avf
 Reciprocal ST depression with or without tall R wave in lead v1-v3
 ST Elevation in lead v7-v9

24. Right coronary artery occlusion-
inferoposterior wall MI

25. Proximal Right coronary artery occlusion –
Inferior and right ventricular MI
ST elevation in lead 2,lead 3,Avf & Lead v1
Reciprocal ST depression in lead 1,aVL

26. Proximal Right coronary artery occlusion –
Inferior wall and right ventricular MI
 ST elevation in lead 2, lead3, Avf
 ST elevation in lead V3r,V4r,V5r,v6R

27. ST depression in lead v1- v3
Posterior wall MI vs Sub endocardial ischemia of anterior wall
 Necessity of thrombolysis
 Confirm with posterior leads( leads v7-v9)
 In Some people left circumflex artery is small and its occlusion does not cause any
changes in ECG( bio markers & angiography needed)

28. Differential diagnosis of ST segment
elevation

29. Thank you