ST Segment Elevations in ECG

1. ST Segment ST Segment
Elevations in Elevations in
ECGECG
K.S. ChewK.S. Chew
School of Medical SciencesSchool of Medical Sciences
Universiti Sains MalaysiaUniversiti Sains Malaysia

2. IntroductionIntroduction
ST segment of the cardiac cycle represents the ST segment of the cardiac cycle represents the
period period betweenbetween depolarization and depolarization and
repolarization of the left ventriclerepolarization of the left ventricle
In normal state, ST segment is isoelectric relative In normal state, ST segment is isoelectric relative
to PR segmentto PR segment

3. IntroductionIntroduction
Most ST segment elevationMost ST segment elevation is a result of is a result of non-non-
AMI causesAMI causes
Otto LA, Aufderheide TP. Evaluation of ST segment Otto LA, Aufderheide TP. Evaluation of ST segment
elevation criteria for the prehospital electrocardiographic elevation criteria for the prehospital electrocardiographic
diagnosis fo acute myocardial infarction. Ann Emerg Med diagnosis fo acute myocardial infarction. Ann Emerg Med
1994; 23 (1):17-24.1994; 23 (1):17-24.
Chan TC, Brady WJ, Harrigan RA et al. ECG in Chan TC, Brady WJ, Harrigan RA et al. ECG in
Emergency Medicine and Acute Care. 1st ed. Emergency Medicine and Acute Care. 1st ed.
Pennsylvania: Elsevier Mosby; 2005.Pennsylvania: Elsevier Mosby; 2005.

4. IntroductionIntroduction
Of 123 adult Of 123 adult chest pain patientschest pain patients withwith ST ST
segment elevation ≥ 1mm,segment elevation ≥ 1mm, 63 patients (51%) did 63 patients (51%) did
not have myocardial infarctions. not have myocardial infarctions.
These non-MI were mainly These non-MI were mainly
LBBB (21%) and LBBB (21%) and
LVH (33%).LVH (33%).
Otto LA, Aufderheide TP. Evaluation of ST segment Otto LA, Aufderheide TP. Evaluation of ST segment
elevation criteria for the prehospital electrocardiographic elevation criteria for the prehospital electrocardiographic
diagnosis fo acute myocardial infarction. Ann Emerg Med diagnosis fo acute myocardial infarction. Ann Emerg Med
1994; 23 (1):17-24.1994; 23 (1):17-24.

5. Causes of ST Segment ElevationCauses of ST Segment Elevation
Acute PericarditisAcute Pericarditis
Benign Early Benign Early
RepolarizationRepolarization
Left Bundle Branch Left Bundle Branch
Block with AMI Block with AMI
(Sgarbossa et al’s criteria)(Sgarbossa et al’s criteria)
Left Ventricular Left Ventricular
HypertrophyHypertrophy
Left Ventricular Left Ventricular
AneurysmAneurysm
Brugada SyndromeBrugada Syndrome
HyperkalemiaHyperkalemia
HypothermiaHypothermia
CNS pathologiesCNS pathologies
Prinzmetal AnginaPrinzmetal Angina
Post electrical Post electrical
cardioversioncardioversion

6. Acute Myocardial InfarctionAcute Myocardial Infarction
Initial ST elevation as part of the classic Initial ST elevation as part of the classic
evolutionary pattern of acute myocardial evolutionary pattern of acute myocardial
infarction was first described by infarction was first described by PardeePardee in 1920 in 1920
Pardee HEB. An electrocardiographic sign of coronary Pardee HEB. An electrocardiographic sign of coronary
artery obstruction. Arch Intern Med 1920; 26: 244–57.artery obstruction. Arch Intern Med 1920; 26: 244–57.

7. Acute Myocardial InfarctionAcute Myocardial Infarction
The exact reasons AMI produces ST segment The exact reasons AMI produces ST segment
elevation are complex and not fully understoodelevation are complex and not fully understood
MI alters MI alters the electrical chargethe electrical charge on the myocardial on the myocardial
cell membranes and produce an abnormal cell membranes and produce an abnormal
current flowcurrent flow
Goldberger: Clinical Electrocardiography: A Simplified Goldberger: Clinical Electrocardiography: A Simplified
Approach, 6th edition, 1999.Approach, 6th edition, 1999.

8. ST segment elevation measured:ST segment elevation measured:
At At J pointJ point – if relative to – if relative to PR segmentPR segment
At At 0.06 – 0.08s0.06 – 0.08s from J point – if relative to from J point – if relative to TP TP
segmentsegment
Chan TC, Brady WJ, Harrigan RA et al. ECG in Chan TC, Brady WJ, Harrigan RA et al. ECG in
Emergency Medicine and Acute Care. 1st ed. Emergency Medicine and Acute Care. 1st ed.
Pennsylvania: Elsevier Mosby; 2005.Pennsylvania: Elsevier Mosby; 2005.
TP segment or PR segment?TP segment or PR segment?

9. ST Segment Elevation RequirementsST Segment Elevation Requirements
1 mm: I,II,III, aVL, aVF, V5-6
2mm: V1-V4
1Minnesota Code
112TAMI
112TIMI
212GUSTO
211GISSI-2
211GISSI-1
112AHA/ACC
Minimum ST
Elevation (mm)
Precordial leads
Minimum ST
Elevation (mm)
Limb leads
Minimum
Consecutive Leads
Study
Chan TC, Brady WJ, Harrigan RA et al. ECG in Emergency Medicine and Acute Care. Chan TC, Brady WJ, Harrigan RA et al. ECG in Emergency Medicine and Acute Care.
1st ed. Pennsylvania: Elsevier Mosby; 2005.1st ed. Pennsylvania: Elsevier Mosby; 2005.

10. Minnesota CodeMinnesota Code
The Minnesota code 9-2 requires ≥1 mm ST The Minnesota code 9-2 requires ≥1 mm ST
elevation in one or more of leads I, II, III, aVL, elevation in one or more of leads I, II, III, aVL,
aVF, V5, V6, or ≥ 2 mm ST elevation in one or aVF, V5, V6, or ≥ 2 mm ST elevation in one or
more of leads V1–V4more of leads V1–V4
Menown IB, Mackenzie G, Adgey AA. Optimizing the Menown IB, Mackenzie G, Adgey AA. Optimizing the
initial 12-lead electrocardiographic diagnosis of acute initial 12-lead electrocardiographic diagnosis of acute
myocardial infarction. Eur Heart J 2000; 21 (4):275-83.myocardial infarction. Eur Heart J 2000; 21 (4):275-83.

11. Irrespective of which definition is used, Irrespective of which definition is used, ST ST
elevation has poor sensitivity for AMIelevation has poor sensitivity for AMI where where
up to 50% of patients exhibit ‘atypical’ changes up to 50% of patients exhibit ‘atypical’ changes
at presentation including isolated ST depression, at presentation including isolated ST depression,
T inversion or even a normal ECGT inversion or even a normal ECG
Menown IB, Mackenzie G, Adgey AA. Optimizing the Menown IB, Mackenzie G, Adgey AA. Optimizing the
initial 12-lead electrocardiographic diagnosis of acute initial 12-lead electrocardiographic diagnosis of acute
myocardial infarction. Eur Heart J 2000; 21 (4):275-83.myocardial infarction. Eur Heart J 2000; 21 (4):275-83.
Acute Myocardial InfarctionAcute Myocardial Infarction

12. Acute Myocardial InfarctionAcute Myocardial Infarction
ST segment elevation MIST segment elevation MI – – persistentpersistent
completecomplete occlusion of an artery supplying a occlusion of an artery supplying a
significant area of myocardium significant area of myocardium without without
adequate collateral circulationadequate collateral circulation
UA/NSTEMI – result from non-occlusive UA/NSTEMI – result from non-occlusive
thrombus, small risk area, brief occlusion, or an thrombus, small risk area, brief occlusion, or an
occlusion with adequate collateralsocclusion with adequate collaterals

13. How To Differentiate STE due to How To Differentiate STE due to
AMI from Other Causes?AMI from Other Causes?
Magnitude of the elevationMagnitude of the elevation
MorphologyMorphology
DistributionDistribution
Prominent Electrical Forces (Voltage Prominent Electrical Forces (Voltage
Amplitude)Amplitude)
QRS widthQRS width
Other FeaturesOther Features

14. Morphology of the ST Morphology of the ST
ElevationElevation

15. Variable Shapes Of ST Segment Variable Shapes Of ST Segment
Elevations in AMIElevations in AMI
Goldberger AL. Goldberger: Clinical Electrocardiography: A Simplified Approach. 7th
ed: Mosby Elsevier; 2006.

16. Morphology of STEMorphology of STE
Concave shape STE – non AMI causesConcave shape STE – non AMI causes
AMIAMI causes – usually demonstrate causes – usually demonstrate
convex/straight STEconvex/straight STE
J point
Apex of T wave
Concave STEConvex STE

17. Notching or slurring of J
point
Concave STE
Benign Early RepolarizationBenign Early Repolarization
Large amplitude T
wave

18. ECG characteristics:ECG characteristics:
2.2.STE STE <2 mm<2 mm
3.3.ConcavityConcavity of initial portion of the ST segment of initial portion of the ST segment
4.4.NotchingNotching or slurring of the terminal QRS complex or slurring of the terminal QRS complex
5.5.Symmetrical, concordant Symmetrical, concordant T wave of large amplitudeT wave of large amplitude
6.6.Widespread or Widespread or diffusediffuse distribution of STE distribution of STE
oDoes not demonstrate territorial distributionDoes not demonstrate territorial distribution
7.7.Relative temporal Relative temporal stabilitystability
Benign Early RepolarizationBenign Early Repolarization

19. Distribution Distribution

20. DistributionDistribution
STE due to AMI usually demonstrate STE due to AMI usually demonstrate regional regional
or territorial patternor territorial pattern
Examples:Examples:
Anterior MI – V3-V4Anterior MI – V3-V4
Septal MI – V2-V3Septal MI – V2-V3
Anteroseptal MI – V1/2 – V4/5Anteroseptal MI – V1/2 – V4/5
Lateral MI – V5/V6Lateral MI – V5/V6
Inferior MI – II, III, aVFInferior MI – II, III, aVF
Diffuse STE – non AMI causes, e.g. pericarditisDiffuse STE – non AMI causes, e.g. pericarditis

21. PericarditisPericarditis
Goldberger AL. Goldberger: Clinical Electrocardiography: A Simplified Approach. 7th
ed: Mosby Elsevier; 2006.

22. 1.1.STE in STE in pericarditispericarditis – – concaveconcave; ; AMIAMI – –
obliquely obliquely flat or convexflat or convex
2.2.STE in STE in pericarditispericarditis – – diffusediffuse; ; AMI AMI – –
territorialterritorial
3.3.PR DepressionPR Depression – – pericarditispericarditis; Q in AMI; Q in AMI
4.4.T inversion in pericarditisT inversion in pericarditis occurs occurs only after only after
ST normalized;ST normalized; T inversion T inversion accompaniesaccompanies
STE in AMI (co-exist)STE in AMI (co-exist)
Differentiating ECG Changes of Differentiating ECG Changes of
AMI vs PericarditisAMI vs Pericarditis

23. PericarditisPericarditis
Goldberger AL. Goldberger: Clinical Electrocardiography: A Simplified Approach. 7th
ed: Mosby Elsevier; 2006.

24. PR segment depression is usually transient but PR segment depression is usually transient but
may be the may be the earliest and most specific signearliest and most specific sign of of
acute myopericarditisacute myopericarditis
Baljepally R, Spodick DH. PR-segment deviation as the Baljepally R, Spodick DH. PR-segment deviation as the
initial electrocardiographic response in acute pericarditis. initial electrocardiographic response in acute pericarditis.
Am J Cardiol 1998; 81 (12):1505-6.Am J Cardiol 1998; 81 (12):1505-6.
PericarditisPericarditis

25. Acute Pericarditis – Four Classical Acute Pericarditis – Four Classical
StagesStages
First described by First described by
Spodick et alSpodick et al
Stage IStage I
first few days first few days  2 weeks 2 weeks
STE, PR depressionSTE, PR depression
Stage IIStage II
last days last days  weeks weeks
Normalization of STENormalization of STE
Stage IIIStage III
after 2-3 weeks, lasts after 2-3 weeks, lasts
several weeksseveral weeks
T wave inversionT wave inversion
Stage IVStage IV
lasts up to several monthslasts up to several months
gradual resolution of T gradual resolution of T
wave changeswave changes
Chan TC, Brady WJ, Pollack M. Electrocardiographic manifestations: acute myopericarditis. J Emerg Chan TC, Brady WJ, Pollack M. Electrocardiographic manifestations: acute myopericarditis. J Emerg
Med 1999; 17 (5):865-72.Med 1999; 17 (5):865-72.

26. Stage 1 PericarditisStage 1 Pericarditis
PR
Depression

27. Stage 2 PericarditisStage 2 Pericarditis

28. Stage 3 PericarditisStage 3 Pericarditis

29. Both demonstrate initial concavity of upsloping ST Both demonstrate initial concavity of upsloping ST
segment/T wavesegment/T wave
PR depression in pericarditis; not in BERPR depression in pericarditis; not in BER
ST/T RatioST/T Ratio
ST/T ratio ≥ 0.25 – pericarditis ST/T ratio ≥ 0.25 – pericarditis
ST/T ratio < 0.25 – BERST/T ratio < 0.25 – BER
Ginzton LE, Laks MM. The differential diagnosis of acute pericarditis Ginzton LE, Laks MM. The differential diagnosis of acute pericarditis
from the normal variant: new electrocardiographic criteria. from the normal variant: new electrocardiographic criteria.
Circulation 1982; 65 (5):1004-9.Circulation 1982; 65 (5):1004-9.
ECG Changes of Pericarditis vs ECG Changes of Pericarditis vs
Benign Early RepolarizationBenign Early Repolarization

30. Brugada Syndrome: Brugada Syndrome:
ECG patternsECG patterns
RBBBRBBB
ST Elevations limited to ST Elevations limited to rightright precordial leads V1 and precordial leads V1 and
V2V2
Saddle shaped or Saddle shaped or coved shapedcoved shaped ST elevation ST elevation
First described in 1992 by Brugada and BrugadaFirst described in 1992 by Brugada and Brugada
The syndrome has been linked to mutations in the
cardiac sodium-channel gene
Amal Mattu, Robert L. Rogers, Hyung Kim, Andrew D. Perron and Amal Mattu, Robert L. Rogers, Hyung Kim, Andrew D. Perron and
William J. Brady. The Brugada Syndrome. The American Journal of William J. Brady. The Brugada Syndrome. The American Journal of
Emergency Medicine, Vol. 21, No. 2, March 2003Emergency Medicine, Vol. 21, No. 2, March 2003

31. ST Elevation morphologies in ST Elevation morphologies in
Brugada SyndromeBrugada Syndrome
RBBB with RSR
pattern rather than
rSR pattern and
there is associated
STE

32. QRS WidthQRS Width

33. Left Bundle Branch BlockLeft Bundle Branch Block
In LBBB, the QRS complex is broad with In LBBB, the QRS complex is broad with
negative QS or rS complex in lead V1, and may negative QS or rS complex in lead V1, and may
demonstrate STEdemonstrate STE
What if, LBBB co-exist with STEMI?What if, LBBB co-exist with STEMI?
Chan TC, Brady WJ, Harrigan RA et al. ECG in Chan TC, Brady WJ, Harrigan RA et al. ECG in
Emergency Medicine and Acute Care. 1st ed. Emergency Medicine and Acute Care. 1st ed.
Pennsylvania: Elsevier Mosby; 2005.Pennsylvania: Elsevier Mosby; 2005.

34. Sgarbossa CriteriaSgarbossa Criteria
Sgarbossa et al. have developed a clinical Sgarbossa et al. have developed a clinical
prediction rule to assist in the ECG diagnosis of prediction rule to assist in the ECG diagnosis of
AMI in the setting of LBBB using three specific AMI in the setting of LBBB using three specific
ECG findingsECG findings
Sgarbossa EB, Pinski SL, Barbagelata A, et al. Sgarbossa EB, Pinski SL, Barbagelata A, et al.
Electrocardiographic diagnosis of evolving acute Electrocardiographic diagnosis of evolving acute
myocardial infarction in the presence of left bundle-myocardial infarction in the presence of left bundle-
branch block. N Engl J Med 1996; 334:481-7.branch block. N Engl J Med 1996; 334:481-7.

35. Sgarbossa CriteriaSgarbossa Criteria
Score 2 points
OR 4.3
ST Elevation ≥ 5 mm and
discordant with QRS
complex
Score 3 points
OR 6.0
ST Depression ≥ 1 mm in
V1, V2, V3
Score 5 points
Odds Ratio (OR) 25.2
ST Elevation ≥ 1 mm and
concordant with QRS
complex
Odds Ratio: a measure of the degree of association; for example, the odds of exposure among the cases compared
with the odds of exposure among the controls (www.cefpas.it/ebm/tools/glossary.htm)

36. AMI in the presence of LBBBAMI in the presence of LBBB

37. A total score of 3 or more suggests that the A total score of 3 or more suggests that the
patient is likely experiencing an AMI based on patient is likely experiencing an AMI based on
the ECG crtieriathe ECG crtieria
With a score less than 3, the ECG diagnosis is With a score less than 3, the ECG diagnosis is
less certain requiring additional evaluationless certain requiring additional evaluation
Chan TC, Brady WJ, Harrigan RA et al. ECG in Chan TC, Brady WJ, Harrigan RA et al. ECG in
Emergency Medicine and Acute Care. 1st ed. Emergency Medicine and Acute Care. 1st ed.
Pennsylvania: Elsevier Mosby; 2005.Pennsylvania: Elsevier Mosby; 2005.
Sgarbossa CriteriaSgarbossa Criteria

38. Subsequent publications have suggested that Sgarbossa’s Subsequent publications have suggested that Sgarbossa’s
criteria is criteria is less useful than reported,less useful than reported, with studies with studies
demonstrating decreased sensitivity and inter-rater demonstrating decreased sensitivity and inter-rater
reliabilityreliability
Shlipak MG, Lyons WL, Go AS et al. Should the electrocardiogram Shlipak MG, Lyons WL, Go AS et al. Should the electrocardiogram
be used to guide therapy for patients with left bundle-branch block be used to guide therapy for patients with left bundle-branch block
and suspected myocardial infarction? Jama 1999; 281 (8):714-9.and suspected myocardial infarction? Jama 1999; 281 (8):714-9.
Edhouse JA, Sakr M, Angus J et al. Suspected myocardial infarction Edhouse JA, Sakr M, Angus J et al. Suspected myocardial infarction
and left bundle branch block: electrocardiographic indicators of acute and left bundle branch block: electrocardiographic indicators of acute
ischaemia. J Accid Emerg Med 1999; 16 (5):331-5.ischaemia. J Accid Emerg Med 1999; 16 (5):331-5.
Sgarbossa CriteriaSgarbossa Criteria

39. Prominent Electrical Prominent Electrical
Forces Forces

40. Left Ventricular HypertrophyLeft Ventricular Hypertrophy

41. ECG Diagnostic Criteria for LVHECG Diagnostic Criteria for LVH
10011R in aVL> 11mm
10011R1 + SIII>25 mm
9642Cornell Voltage Criteria
SV3+RaVL>28 mm (men), 20mm(women)
10022Sokolow-Lyon Index
SV1 + (RV5 or RV6)>35mm
SpecificitySensitivity
Other Criteria include Romhilt and Estes Point Score System
Chan TC, Brady WJ, Harrigan RA et al. ECG in Emergency Medicine and Chan TC, Brady WJ, Harrigan RA et al. ECG in Emergency Medicine and
Acute Care. 1st ed. Pennsylvania: Elsevier Mosby; 2005.Acute Care. 1st ed. Pennsylvania: Elsevier Mosby; 2005.

42. The initial upsloping of the elevated ST segment The initial upsloping of the elevated ST segment
is frequently is frequently concave in LVH concave in LVH as opposed to as opposed to
the more likely flat/convex ST segment the more likely flat/convex ST segment
elevation in ACSelevation in ACS
The T wave is usually asymmetrical in LVHasymmetrical in LVHas
opposed to the symmetrical T wave seen in
coronary ischemia
ECG Changes of Left Ventricular ECG Changes of Left Ventricular
Hypertrophy vs AMIHypertrophy vs AMI

43. ConclusionConclusion
Not all STE are due to STEMINot all STE are due to STEMI
ECG remains a good diagnostic tool, but must ECG remains a good diagnostic tool, but must
be correlated with clinical history and physical be correlated with clinical history and physical
examinationexamination
Certain characteristics of the ECG changes may Certain characteristics of the ECG changes may
aid in the correct diagnosis: morphology, aid in the correct diagnosis: morphology,
distribution, associated QRS complexes, voltage distribution, associated QRS complexes, voltage
forces, etc.forces, etc.

44. ReferencesReferences
Wang K, Asinger RW, Marriott HJ. ST-segment Wang K, Asinger RW, Marriott HJ. ST-segment
elevation in conditions other than acute elevation in conditions other than acute
myocardial infarction. N Engl J Med 2003; 349 myocardial infarction. N Engl J Med 2003; 349
(22):2128-35.(22):2128-35.
Chan TC, Brady WJ, Harrigan RA et al. ECG in Chan TC, Brady WJ, Harrigan RA et al. ECG in
Emergency Medicine and Acute Care. 1st ed. Emergency Medicine and Acute Care. 1st ed.
Pennsylvania: Elsevier Mosby; 2005.Pennsylvania: Elsevier Mosby; 2005.

45. ReferencesReferences
Goldberger: Clinical Electrocardiography: A Simplified Goldberger: Clinical Electrocardiography: A Simplified
Approach, 6th edition, 1999.Approach, 6th edition, 1999.
William J. Brady, Theodore C. Chan. William J. Brady, Theodore C. Chan.
Electrocardiographic Manifestations: Benign Early Electrocardiographic Manifestations: Benign Early
Repolarization. The Journal of Emergency Medicine, Repolarization. The Journal of Emergency Medicine,
Vol. 17, No. 3, pp. 473–478, 1999Vol. 17, No. 3, pp. 473–478, 1999
Sgarbossa EB, Pinski SL, Barbagelata A, et al. Sgarbossa EB, Pinski SL, Barbagelata A, et al.
Electrocardiographic diagnosis of evolv-ing acute Electrocardiographic diagnosis of evolv-ing acute
myocardial infarction in the presence of left bundle-myocardial infarction in the presence of left bundle-
branch block. N Engl J Med 1996; 334:481-7.branch block. N Engl J Med 1996; 334:481-7.