This document discusses the role of electrocardiograms (ECGs) in diagnosing ST-segment elevation myocardial infarction (STEMI). It describes how ECGs can be used to: 1) Diagnose acute STEMI based on specific ST elevation patterns and cardiac marker changes. 2) Determine candidates for reperfusion therapy. 3) Assess the success of reperfusion therapy by observing the resolution of ST elevation. It then outlines the typical ECG patterns seen in different types of STEMI based on the affected coronary artery.

1. ECG IN STEMI
DR AZERIN OTHMAN
HRPZ II KOTA BHARU
STEMIWORKSHOP

2. • Diagnosis of acute STEMI
• Correlate ECG changes and candidate for reperfusion
therapy
• Assess the success of reperfusion therapy
• Correlate location of MI & extent of myocardial
injury - stratification/prognostication/complications
- optimal treatment
ROLES OF ECG IN STEMI

3. CORONARY ARTERIES

4. CLINICAL DIAGNOSIS OF ACUTE STEMI
1.Chest pain or equivalent symptoms or events suggestive ischaemic in origin.
+
2.ECG changes : Any of the followings (on its own or in any combinations):
 ST elevation in 2 or more contiguous leads of standard 12 lead ECG as
follows:
 Posterior Infarction
 RV Infarction
 New onset LBBB
+
3.Elevated cardiac markers
4
- ≥ 1mm limb leads : I, aVL, II, III, aVF.
- ≥ 1mm precordial leads : V4 - V6.
- ≥ 2 mm precordial leads : V1 - V3 .

5. Other causes of raised cardiac markers
– CKMB & Troponin

6. ECG CHANGES IN STEMI
1.HYPERACUTE PEAK T WAVE - HYPERACUTE T WAVE
- T waves tall, symmetrical & peaked
- usually present 5- 30 minutes after the onset of MI later followed by ST
changes.

7. ECG CHANGES IN STEMI
2.ST SEGMENT ELEVATION - HYPERACUTE ST ELEVATION
- commonly seen
- usually within hours after onset of MI
- occurs in the leads facing the infarction

8. ECG CHANGES IN STEMI
3. PATHOLOGICAL Q WAVE - FULLY EVOLVED PHASE
- at least 0.04 seconds in duration
- depth of more than 25% of ensuing R wave
- usually after 9 hours, occasionally after 24 hours after onset of MI
- evidence of myocardial necrosis
- loss of R wave after 12 hours

9. ECG CHANGES IN STEMI
4.RESOLUTION OF ST ELEVATION & T WAVE INVERSION - RESOLUTION PHASE
- ST segment elevation diminishes and T wave inverted.
- occurs around 1 week

10. ECG CHANGES IN STEMI
5.RESOLUTION OF ST ELEVATION & T WAVE INVERSION - CHRONIC PHASE
- persistent Q wave or reduced /poor R wave
- T wave normalised.
- occurs after months-years

11. SEQUENCE OF ECG CHANGES IN STEMI

13. ST ELEVATION IN ACUTE STEMI
ST elevation in 2 or more contiguous leads of
standard 12 lead ECG as follows:
- ≥ 1mm limb leads : I, aVL, II, III, aVF.
- ≥ 1mm precordial leads : V4 - V6.
- ≥ 2 mm precordial leads : V1 - V3 .

14. Inferior STEMI
• ST elevation: II,III,aVF
• Reciprocal ST depression :
I,aVL
• Infarct artery: RCA (80%)
LCX (20%)

15. Anteroseptal STEMI
• ST elevation: V1-V4
• Can have reciprocal ST
depression inferior leads
• Infarct artery : LAD

16. Extensive Anterior STEMI
• ST elevation: I,aVL,
V1-V6.
• Can have reciprocal ST
depression inferior leads
• Infarct artery : LAD

17. Anterior STEMI
• ST elevation: V1-V6.
• Can have reciprocal ST
depression inferior leads
• Infarct artery : LAD

18. Lateral STEMI
• ST elevation: I,aVL ,
V5-V6.
• Can have reciprocal ST
depression inferior leads
• Infarct artery : LCX

19. Posterior infarction
• Usually associated with inferior and/or lateral
and or RV STEMI
• 4% occur alone - called true/isolated posterior
STEMI
• ECG of posterior infarction are :
 ST depression ≥ 1mm (0.1mv) with upright T wave precordial leads : V1 - V4
and / or
 ST elevation ≥ 1mm (0.1mv) in the posterior leads : V7 - V9
and / or
 Tall R wave and duration ≥ 0.04s precordial leads : V1 or V2
and / or
 The ratio of the R / S wave > 1 precordial leads : V1 or V2
*Some use ST elevation ≥ 0.5mm in V7-V9 for diagnosis of posterior MI

20. True posterior STEMI
 ST depression ≥ 1mm (0.1mv) with uprightT wave precordial leads :
V1 –V3

21. If we flip or view ECG
posteriorly
 ST depression ≥ 1mm (0.1mv) with uprightT wave precordial leads :
V1 –V3  ST elevation when view ECG posteriorly

23.  ST depression ≥ 1mm (0.1mv) in leads : V1-V3  ST elevation ≥ 1mm (0.1mv) in leads : V7-V9

24. Other posterior leads placement….
LEADV1 → LEAD V7
LEAD V2 → LEAD V8
LEAD V3 → LEAD V9

25. ECG-POSTERIOR STEMI
 Tall R wave and duration ≥ 0.04s
precordial leads : V1 or V2
 The ratio of the R / S wave > 1
precordial leads : V1 or V2
Flip back
 OTHER CAUSES OFTALL R -V1-V2

26. TRUE POSTERIOR INFARCTION
• ST depression + upright T: V1-V4
and/or
• ST elevation : V7-V9
and/or
• Tall R wave and duration ≥ 0.04s
precordial leads : V1 or V2
and /or
• The ratio of the R / S wave > 1
precordial leads : V1 or V2
• Infarct artery : LCX
POSTERIOR LEADS

27. Infero - lateral - posterior STEMI
• ST elevation : II,III,aVF
V4-V6
• ST depression: V1-V3
• Infarct artery : RCA
 ST depression ≥ 1mm (0.1mv)
with uprightT wave precordial leads :
V1 –V2

28. RV INFARCTION
• Usually with inferior STEMI & ST elevation is
transient, disappearing in less than 10 hours
following its onset in half of patients.
• Do right sided ECG in all inferior STEMI
• ECG of RV infarction is

29. Do right sided ECG

30. • ST elevation : RV3 ,RV4
• Usually asstd : inferior
STEMI
• Infarct artery : RCA

31. LBBB AND STEMI
• New onset LBBB - as STEMI presentation
• STEMI AS LBBB - higher hospital mortality
• Guidelines  new LBBB  STEMI  reperfusion RX
• Beside STEMI  many other causes of LBBB
• LBBB obscure classical STEMI ECG-Q wave & ST-T changes

• How do we predict the likelihood of LBBB as true STEMI
( the best & goal standard is coronary angiogram !!)
 
BUT…. PCI NOT READILY AVAILABLE
EVERYWHERE & WITHIN TIME
?? ENSURE GIVE FIBRINOLYSIS
TO “TRUE “ STEMI…

32. LBBB IN STEMI
LBBB can be associated with
STEMI in the following ways
• True STEMI - with massive
myocardial damage
• Preexisting LBBB with acute
STEMI
• Transient ischemic LBBB during
STEMI
• Rate dependent LBBB (Usually
tachycardia related )
• STEMI in pacemaker rhythms
CAUSES OF LBBB
- STEMI
- HYPERTENSION
- AORTIC VALVE DISEASE
- EXTENSIVE CAD
- DEGENERATIVE DISEASE
- CONGENITAL HEART
DISEASE
- PACEMAKER RHYTHM

33. So we analyse with ….
SGARBOSSA
CRITERIA

34. SGARBOSSA CRITERIA
CRITERIA 1:
ST ELEVATION > 1MM IN ANY CONCORDANT
LEAD ( POSITIVEQRS)
SCORE : 5 - MOST PREDICTIVE
CRITERIA 2:
ST DEPRESSION > 1MM IN ANY LEAD V1-V3
SCORE : 3
CRITERIA 3:
ST ELEVATION > 5MM IN ANY DISCORDANT
LEAD ( NEGATIVE QRS)
SCORE : 2 - LEAST PREDICTIVE
SCORE ≥ 3 : 90% SPECIFIC FOR STEMI & CUTPOINT USED

35. LBBB + INFERIOR STEMI
LBBB + ST > 1mm in lead with a positiveQRS complex ( lead II) → score 5
likely STEMI as score ≥ 3

36. LBBB + ANTERIOR MI
LBBB + ST elevation > 1mm in leads with positive QRS complex ( V4-V5)→ score 5
likely STEMI as score ≥ 3

37. LBBB
LBBB + ST elevation > 5mm in leads with negative QRS complex (V1-V3) → score 2
 unlikely STEMI as score < 3

38. LBBB AND PROBABILITY OF STEMI

39. CLINICAL ASSESSMENTOF SUCCESSFUL
REPERFUSION
 RESOLUTION OF CHEST PAIN
 ABSOLUTE RESOLUTION OF ST ELEVATION OR
REDUCTION OF ≥ 50% OF ST ELEVATION
 EARLY PEAK CARDIAC ENZYME
 IDIOVENTRICULAR RHYTHM
 TWAVE INVERSION WITHIN 4 HOURS

40. PRE REPERFUSION RX POST REPERFUSION RX-90 MIN
CLINICAL ASSESSMENT OF SUCCESSFUL
REPERFUSION

41. Correlation location of STEMI & clinical outcome