how to localize the CULPRIT ARTERY OCCLUSION in MI from ECG

1. ECG localization of
Myocardial Infarction.
-DR SHLESHA R PRADHAN

2. Coronary Arteries

3. BRANCHES:-
 Right coronary artery
• Conus branch
• AV Nodal branch
• RV branch
• Acute marginal branch
• Posterior descending artery(PDA)
• Posteriolateral artery(PL)
 Left coronary artery/ Left main
coronary artery
• Left anterior descending artery(LAD)
o Septal branches(S1,S2,S3)
o Diagonal branches(D1,D2,D3)
• Left circumflex artery(LCX)
o Atrial branch
o Obtuse marginals(OM1,OM2)
o Posteriolateral branch

4. Blood Supply Of Heart:-
 Anterior segment- LAD(Septal perforating branches)
 Anterior wall- LAD(Diagonal branches)
 Lateral wall- Circumflex(Obtuse Marginal branches)
 Posterior wall- Right Coronary artery(Extension branches)
Circumflex(Obtuse Marginal branches)
 Inferior Septum- Posterior descending artery
 Inferior Wall- Posterior descending artery
 Apex- LAD and or PD artery

5. SA node- RCA in 65%
AV node- RCA in 90%

6. Dominance of Coronary Artery:-
 Supplies circulation to inferior wall and inferior portion of posterior septum
 Passes crux and IVS, giving rise to PDA and Posterolateral branches
 Also give rise to AV Nodal branch
 Non dominant artery- smaller in size, terminates early
 CODOMINANT coronary circulation- posterior crux of heart receive twigs from both right and
left system, making this water-shed area have advantage of twin supply
RCA-70%
LCX-10%
Co-dominant-20%

7. Dominance of Coronary Artery:-
right Left CO

8. The Concept of Injury Vector- Direct and
Reciprocal changes
 Injury Vector is oriented towards the injured area and generates ST
Elevation in the leads facing the Vector’s head.
 ST Depression in the leads facing the Vector’s tail(opposed leads).
 Leads perpendicular to dominant Vector will record an Isoelectrical ST
segment.
 ST Elevation in one territory often have ST Depression in other territories.
 The additional ST Deviation may represent ischemia due to coronary disease
in non infarct related arteries(ischemia at distance) or may represent pure
“mirror image” reciprocal changes

9. The Concept of Injury Vector- Direct and
Reciprocal changes

10. The Concept of Injury Vector- Direct and
Reciprocal changes
Proximal LAD
Distal LAD
RCA
LCX

11. ST Elevation and ST Depression CUT-OFFS:-

12. ECG Changes in prior MI

13. Q Wave and Non Q Wave Infarction
 The presence or absence of Q waves on the surface ECG does
not reliably distinguish between transmural and
nontransmural/subendocardial Infarct.
 Q Wave on ECG signify abnormal electrical activity but not
synonymous with irreversible myocardial damage.
 Also, absence of Q Wave may simply reflect the insensitivity
of standard 12 lead ECG, especially in zones of LV supplied by
LCX.

14. The Progression during acute coronary
Occlusion and Reperfusion

17. ECG Localization:-

19. Left anterior descending
Artery supply..
• Anterior wall (by Diagonal
artery) {1, 7,13}.
• Anterior part of septum
(by Septal artery) {2,8,14}.
• RBB { by 1ST Septal }
• Apex (17)
• Sometimes segment 15.

20. Right coronary artery
supplies..
• Right ventricle.
• Inferior wall {4, 10, 15}.
• Inferior septum{ 3 ,9,
15}.
• Sometimes part of
Lateral wall { 5, 11, 16}.

21. Left circumflex
artery supplies..
• Anterior lateral
wall {6, 12, 16}.
• Inferior lateral
wall { 5, 11}.
• (if Dominant) Part
of Inferior wall {4,
10, 15}.

22. Anterior Wall Myocardial Infarction
 Proximal to 1st Septal and 1st Diagonal branch (40%)
 Distal to Septal and Diagonal branches (40%)
 Proximal to D1 but distal to S1 (5%)
 Proximal to S1 but distal to D1(5%)
 Selective D1 D2 occlusion
 Selective S1 S2 occlusion
AnteroSeptal Zone : occlusion of LAD and its branches

24. Proximal LAD Occlusion
(Dominance of basal area)
INJURY VECTOR- Anterior and Upwards to right or left
 ST Elevation in aVR and V1 >= 2.5 mm
 ST Depression in inferior leads(II III aVF) and in V5
 Abnormal Q wave in aVL
 ST Depression in III + aVF >= 2.5 mm

26. Distal LAD Occlusion
(Dominance of InferoApical area)
 Absence of ST depression in INFERIOR
LEADS
 Distal to S1 – Abnormal Q wave in V4-V6
 Distal to D1- ST Depression in aVL

28. Proximal to S1, Distal to D1
(Dominance of Septal area)
 Antero septal infarction
 ST Elevation in aVR and V1 >= 2.5 mm
 ST Elevation in V1-V3/V4 and in II III aVF
 ST Depression in V6, I, aVL
 ST Elevation in V3R
 RBBB/QRBBB

30. Proximal to D1, Distal to S1
(Dominance of Lateral area)
 ST Elevation in aVL and lead I
 Q waves in lateral leads
 ST Depression in lead III >lead II
 ST Depression in lead III + aVF >= 2.5 mm

32. Selective Occlusion of D1 branch
INJURY VECTOR- Upwards Forwards and to Left
 Area affected- Mid Low Anterior wall and Mid Low
lateral wall
 ST Elevation in I, aVL and precordial leads V2-
V6(variable)
 ST Depression in II, III, aVF (lead III > lead II)

34. Selective Occlusion of S1 branch
INJURY VECTOR- Anteriorly Upward and to Right
 Area affected- Septal wall with occasionally certain
extension to Anterior wall
 ST Elevation in V1,V2, aVR
 ST Depression in II, III, aVF (lead II > lead III) and V6
 No ST Elevation in aVL

35. Inferior Wall Myocardial Infarction
INJURY VECTOR

38. Occlusion of RCA
 ST Elevation in lead III > lead II
 ST Depression in lead I and aVL
 ST Depression in Right precordial leads < Inferior leads
 PROXIMAL OCCLUSION:-
STE in V1 >V3 V4
STD in V3: STE in III < 0.5
 DISTAL OCCLUSION:-
STD in V3: STE in III = 0.5 to 1.2

40. Occlusion of LCX
 ST Elevation in lead II > lead III
 ST Elevation (isoelectric) in lead I and aVL
 STE in Inferior leads < right precordial leads
 If LCX is dominant Then… .. ST Depression in aVL, ST
Elevation in lead I and V5 V6

43. Lead V4R

45. Right ventricular Myocardial Infarction
 14 to 36%
 ST Elevation in lead III > II
 ST Elevation in V3R and V4R
 ST Elevation in V1 to V3, V1>V2
 ST Elevation in V1 , ST Depression in V2 (discordant)
 ST Depression in V2 >= 50% of ST Elevation in aVF

46. Posterior Wall Myocardial Infarction
 ST Depression in Precordial Leads with R waves and upright
T waves
 Generally V1 to V4, may extent to V6 in case of large MI
 Maximal ST depression in V4-V6, is seen in TVD and low
LVEF
 Can occur in both RCA or LCX artery involvement

48. Myocardial Infarction in BBB.
IN RBBB IN LBBB

51. Other ECG Changes in patient of MI with
LBBB:-
 LBBB is associated with 7% of all infarcts
 Presence of abnormal Q wave
 Notching of S waves (CABRERA SIGN)
 Regression of R wave in precordial leads(V1 to V6)
 Notching of R waves (CHAPMAN SIGN)
 LEFT axis deviation

53. OCCLUSION
Multivessal
LCX
LAD
RCA
Inf. MI with ST
dep. In V4-V6.
INFERIOR WALL
MI +
a) with ST elev. In
II >III.
b) with ST dep in
aVL and in V1-
V3.
c) with ST elev. In
V5-V6.
d) V3 ST dep: III
ST elev. > 1.2.
INFERIO
R MI
with ST
elev. In
III> II.
Proximal
Distal
a) ST elev. In V2.
b) V3 ST dep: III
ST elev.< 0.5.
V3 ST
dep: III ST
elev 0.5-
1.2.
ANT. MI
with ST
dep. >=1
in inf.
leads
ANT. MI
with NO
ST dep. in
inf. Leads.
Distal
Proxim
al
Proximal to S1
•ST elev. In
V1>2.5mm
•ST elev in
aVR.
•ST dep. in V5.
Proximal to
D1
•Abn. Q in
aVL.
Distal to S1
•Abn. Q in
V4-V6.
Distal to
D1
• ST dep.

54. PROGNOSTIC VALUE of ECG in MI:-
 Q wave V/S Non Q wave infarction
 Site of Infarction
 Anterior wall
 Inferior wall- reciprocal ST depression in V1-V4
Complete AV Block
Extensive RV infarction
 Abnormal T waves
 Higher T wave amplitude- better
 Q wave MI with STE>2mm and positive T waves- large infarct, less chance of reoccurance
 Inverted T waves in QMI indicates Transmural infarct

55.  Associated BBB
 LBBB- 34% increase risk of in hospital mortality
 BBB – associated with 53% higher risk of 30 day mortality (GUSTO-1 Trial)
 AV block – 20% mortality then 4% in non AV block (TAMI trial)
 QT dispersion- risk of Arrythmia

56. Acute MI : Culprit Artery and Mortality

57. ECG pattern hinting for high risk critical
coronary artery disease:

58. ECG pattern hinting for high risk critical
coronary artery disease:

59. Spotter !

60. Left main occlusion or Triple Vessal
Disease:
 Marked downsloping ST depressions in I, II, V4-V6 and ST Elevation
in aVR.
 aVR STE more in LMCA than LAD
 V1 STE less in LMCA then LAD
 Higher mortality rate for those with higher STE in aVR
 Acute LMCA occlusion causes serious hemodynamic deterioration,
but more commonly seen is subtotal occlusion with collaterals from
RCA.

61. Is ST Elevation in aVR Bad?

62. SPOTTER!
IWMI
+RVMA=RCA

63. CONCLUSION:-
 Sensitivity of ECG for Autopsy proven MI is 55 to 61%
 ECG provides important information about culprit artery and
site of occlusion
 ST Elevation equivalents should not be missed
 Important prognostic value

64. Thankyou