ST Segment Elevations in ECG

ST ST Segment Segment Elevations Elevations in ECGin ECGSan Juan County San Juan County EMSEMS

Paramedic Run Paramedic Run Review 2011Review 2011

IntroductionIntroduction

ST segment of the cardiac cycle ST segment of the cardiac cycle represents the period represents the period betweenbetween depolarization and repolarization of depolarization and repolarization of the left ventriclethe left ventricle

In normal state, ST segment is In normal state, ST segment is isoelectric relative to PR segmentisoelectric relative to PR segment

IntroductionIntroduction

Most ST segment elevationMost ST segment elevation is a result is a result of of non-AMI causesnon-AMI causes

Otto LA, Aufderheide TP. Evaluation of ST Otto LA, Aufderheide TP. Evaluation of ST segment elevation criteria for the prehospital segment elevation criteria for the prehospital electrocardiographic diagnosis fo acute electrocardiographic diagnosis fo acute myocardial infarction. Ann Emerg Med 1994; myocardial infarction. Ann Emerg Med 1994; 23 (1):17-24.23 (1):17-24.

Chan TC, Brady WJ, Harrigan RA et al. ECG Chan TC, Brady WJ, Harrigan RA et al. ECG in Emergency Medicine and Acute Care. 1st in Emergency Medicine and Acute Care. 1st ed. Pennsylvania: Elsevier Mosby; 2005.ed. Pennsylvania: Elsevier Mosby; 2005.

IntroductionIntroduction Of 123 adult Of 123 adult chest pain patientschest pain patients withwith

ST segment elevation ≥ 1mm,ST segment elevation ≥ 1mm, 63 63 patients (51%) did not have myocardial patients (51%) did not have myocardial infarctions. 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 Otto LA, Aufderheide TP. Evaluation of ST segment elevation criteria for the prehospital segment elevation criteria for the prehospital electrocardiographic diagnosis fo acute electrocardiographic diagnosis fo acute myocardial infarction. Ann Emerg Med 1994; 23 myocardial infarction. Ann Emerg Med 1994; 23 (1):17-24.(1):17-24.

Causes of ST Segment Causes of ST Segment ElevationElevation

Acute PericarditisAcute Pericarditis Benign Early Benign Early

RepolarizationRepolarization Left Bundle Left Bundle

Branch Block with Branch Block with AMI (Sgarbossa et AMI (Sgarbossa et al’s criteria)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

Acute Myocardial Acute Myocardial InfarctionInfarction

Initial ST elevation as part of the Initial ST elevation as part of the classic evolutionary pattern of acute classic evolutionary pattern of acute myocardial infarction was first myocardial infarction was first described by described by PardeePardee in 1920 in 1920

Pardee HEB. An electrocardiographic sign Pardee HEB. An electrocardiographic sign of coronary artery obstruction. Arch Intern of coronary artery obstruction. Arch Intern Med 1920; 26: 244–57.Med 1920; 26: 244–57.


The exact reasons AMI produces ST The exact reasons AMI produces ST segment elevation are complex and segment elevation are complex and not fully understoodnot fully understood

MI alters MI alters the electrical chargethe electrical charge on on the myocardial cell membranes and the myocardial cell membranes and produce an abnormal current flowproduce an abnormal current flow

Goldberger: Clinical Electrocardiography: A Goldberger: Clinical Electrocardiography: A Simplified Approach, 6th edition, 1999.Simplified Approach, 6th edition, 1999.

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 from J point – if

relative to relative to TP segmentTP segment


TP segment or PR TP segment or PR segment?segment?

ST Segment Elevation ST Segment Elevation RequirementsRequirements

StudyStudy Minimum Minimum Consecutive Consecutive LeadsLeads

Minimum ST Minimum ST Elevation Elevation (mm) Limb (mm) Limb leadsleads

Minimum ST Minimum ST Elevation Elevation (mm) (mm) Precordial Precordial leadsleads

AHA/ACCAHA/ACC 22 11 11

GISSI-1GISSI-1 11 11 22

GISSI-2GISSI-2 11 11 22

GUSTOGUSTO 22 11 22

TIMITIMI 22 11 11

TAMITAMI 22 11 11Minnesota Minnesota CodeCode

11 1 mm: I,II,III, aVL, aVF, V5-61 mm: I,II,III, aVL, aVF, V5-6

2mm: V1-V42mm: V1-V4Chan TC, Brady WJ, Harrigan RA et al. ECG in Emergency Chan TC, Brady WJ, Harrigan RA et al. ECG in Emergency Medicine and Acute Care. 1st ed. Pennsylvania: Elsevier Mosby; Medicine and Acute Care. 1st ed. Pennsylvania: Elsevier Mosby; 2005.2005.

Minnesota CodeMinnesota Code

The Minnesota code 9-2 requires ≥1 The Minnesota code 9-2 requires ≥1 mm ST elevation in one or more of mm ST elevation in one or more of leads I, II, III, aVL, aVF, V5, V6, or ≥ leads I, II, III, aVL, aVF, V5, V6, or ≥ 2 mm ST elevation in one or more of 2 mm ST elevation in one or more of leads V1–V4leads V1–V4

Menown IB, Mackenzie G, Adgey AA. Menown IB, Mackenzie G, Adgey AA. Optimizing the initial 12-lead Optimizing the initial 12-lead electrocardiographic diagnosis of acute electrocardiographic diagnosis of acute myocardial infarction. Eur Heart J 2000; 21 myocardial infarction. Eur Heart J 2000; 21 (4):275-83.(4):275-83.

Irrespective of which definition is used, Irrespective of which definition is used, ST elevation has poor sensitivity for ST elevation has poor sensitivity for AMIAMI where up to 50% of patients where up to 50% of patients exhibit ‘atypical’ changes at exhibit ‘atypical’ changes at presentation including isolated ST presentation including isolated ST depression, T inversion or even a normal depression, T inversion or even a normal ECGECG

Menown IB, Mackenzie G, Adgey AA. Optimizing Menown IB, Mackenzie G, Adgey AA. Optimizing the initial 12-lead electrocardiographic diagnosis the initial 12-lead electrocardiographic diagnosis of acute myocardial infarction. Eur Heart J 2000; of acute myocardial infarction. Eur Heart J 2000; 21 (4):275-83.21 (4):275-83.



ST segment elevation MIST segment elevation MI – – persistentpersistent completecomplete occlusion of occlusion of an artery supplying a significant an artery supplying a significant area of myocardium area of myocardium without without adequate collateral circulationadequate collateral circulation

UA/NSTEMI – result from non-UA/NSTEMI – result from non-occlusive thrombus, small risk area, occlusive thrombus, small risk area, brief occlusion, or an occlusion with brief occlusion, or an occlusion with adequate collateralsadequate collaterals

How To Differentiate STE How To Differentiate STE due to AMI from Other due to AMI from Other

Causes?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

Morphology of the Morphology of the ST ElevationST Elevation

Variable Shapes Of ST Variable Shapes Of ST Segment Elevations in AMISegment Elevations in AMI

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

Morphology of STEMorphology of STE

Concave shape STE – non AMI Concave shape STE – non AMI causescauses

AMIAMI causes – usually demonstrate causes – usually demonstrate convex/straight STEconvex/straight STE

J point

Apex of T wave

Concave STE

Convex STE

Notching or slurring of J point

Concave STE

Benign Early Benign Early RepolarizationRepolarization

Large amplitude T wave

ECG characteristics:ECG characteristics:

1.1. STE STE <2 mm<2 mm

2.2. ConcavityConcavity of initial portion of the ST segment of initial portion of the ST segment

3.3. NotchingNotching or slurring of the terminal QRS or slurring of the terminal QRS complexcomplex

4.4. Symmetrical, concordant Symmetrical, concordant T wave of large T wave of large amplitudeamplitude

5.5. Widespread or Widespread or diffusediffuse distribution of STE distribution of STEo Does not demonstrate territorial distributionDoes not demonstrate territorial distribution

6.6. Relative temporal Relative temporal stabilitystability

Benign Early Benign Early RepolarizationRepolarization

Distribution Distribution

DistributionDistribution

STE due to AMI usually demonstrate STE due to AMI usually demonstrate regional or territorial patternregional or 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. Diffuse STE – non AMI causes, e.g. pericarditispericarditis

PericarditisPericarditis


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 ; Q in AMIAMI

4.4. T inversion in pericarditisT inversion in pericarditis occurs occurs only after ST normalized;only after ST normalized; T inversion T inversion accompaniesaccompanies STE in AMI (co-exist)STE in AMI (co-exist)

Differentiating ECG Differentiating ECG Changes of AMI vs Changes of AMI vs


PR segment depression is usually PR segment depression is usually transient but may be the transient but may be the earliest and earliest and most specific signmost specific sign of acute of acute myopericarditismyopericarditis

Baljepally R, Spodick DH. PR-segment Baljepally R, Spodick DH. PR-segment deviation as the initial electrocardiographic deviation as the initial electrocardiographic response in acute pericarditis. Am J Cardiol response in acute pericarditis. Am J Cardiol 1998; 81 (12):1505-6.1998; 81 (12):1505-6.


Acute Pericarditis – Four Acute Pericarditis – Four Classical StagesClassical Stages

First described by First described by Spodick et alSpodick et al

Stage IStage I first few days first few days 2 2

weeksweeks STE, PR STE, PR

depressiondepression Stage IIStage II

last days last days weeks weeks Normalization of Normalization of

STESTE

Stage IIIStage III after 2-3 weeks, after 2-3 weeks,

lasts several weekslasts several weeks T wave inversionT wave inversion

Stage IVStage IV lasts up to several lasts up to several

monthsmonths gradual gradual

resolution of T resolution of T wave changeswave changes

Chan TC, Brady WJ, Pollack M. Electrocardiographic manifestations: acute Chan TC, Brady WJ, Pollack M. Electrocardiographic manifestations: acute myopericarditis. J Emerg Med 1999; 17 (5):865-72.myopericarditis. J Emerg Med 1999; 17 (5):865-72.

Stage 1 PericarditisStage 1 Pericarditis

PR Depression

Both demonstrate initial concavity of Both demonstrate initial concavity of upsloping ST segment/T waveupsloping ST segment/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 Ginzton LE, Laks MM. The differential diagnosis of acute pericarditis from the normal variant: new acute pericarditis from the normal variant: new electrocardiographic criteria. Circulation 1982; 65 electrocardiographic criteria. Circulation 1982; 65 (5):1004-9.(5):1004-9.

ECG Changes of ECG Changes of Pericarditis vs Benign Early Pericarditis vs Benign Early

RepolarizationRepolarization

Brugada Syndrome: Brugada Syndrome: ECG patternsECG patterns

RBBBRBBB ST Elevations limited to ST Elevations limited to rightright precordial leads precordial leads

V1 and V2V1 and V2 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 Amal Mattu, Robert L. Rogers, Hyung Kim, Andrew D. Perron

and William J. Brady. The Brugada Syndrome. The American and William J. Brady. The Brugada Syndrome. The American Journal of Emergency Medicine, Vol. 21, No. 2, March 2003Journal of Emergency Medicine, Vol. 21, No. 2, March 2003

ST Elevation morphologies ST Elevation morphologies in Brugada Syndromein Brugada Syndrome

RBBB with RSR pattern rather than rSR pattern and there is associated STE

QRS WidthQRS Width

Left Bundle Branch Left Bundle Branch BlockBlock

In LBBB, the QRS complex is broad In LBBB, the QRS complex is broad with negative QS or rS complex in with negative QS or rS complex in lead V1, and may lead V1, and may demonstrate STEdemonstrate STE

What if, LBBB co-exist with STEMI?What if, LBBB co-exist with STEMI?


Sgarbossa CriteriaSgarbossa Criteria

Sgarbossa et al. have developed a Sgarbossa et al. have developed a clinical prediction rule to assist in the clinical prediction rule to assist in the ECG diagnosis of AMI in the setting of ECG diagnosis of AMI in the setting of LBBB using three specific ECG findingsLBBB using three specific ECG findings

Sgarbossa EB, Pinski SL, Barbagelata A, et al. Sgarbossa EB, Pinski SL, Barbagelata A, et al. Electrocardiographic diagnosis of evolving Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of acute myocardial infarction in the presence of left bundle-branch block. N Engl J Med 1996; left bundle-branch block. N Engl J Med 1996; 334:481-7.334:481-7.


ST Elevation ST Elevation ≥ 1 mm ≥ 1 mm and concordant with and concordant with QRS complexQRS complex

Score 5 pointsScore 5 points

Odds Ratio (OR) 25.2Odds Ratio (OR) 25.2

ST Depression ST Depression ≥ 1 ≥ 1 mm in V1, V2, V3mm in V1, V2, V3


OR 6.0OR 6.0

ST Elevation ST Elevation ≥ 5 mm ≥ 5 mm and discordant with and discordant with QRS complexQRS complex


OR 4.3OR 4.3

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)

AMI in the presence of AMI in the presence of LBBBLBBB

A total score of 3 or more suggests that A total score of 3 or more suggests that the patient is likely experiencing an the patient is likely experiencing an AMI based on the ECG crtieriaAMI based on the ECG crtieria

With a score less than 3, the ECG With a score less than 3, the ECG diagnosis is less certain requiring diagnosis is less certain requiring additional evaluationadditional 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.


Subsequent publications have suggested that Subsequent publications have suggested that Sgarbossa’s criteria is Sgarbossa’s criteria is less useful than less useful than reported,reported, with studies demonstrating with studies demonstrating decreased sensitivity and inter-rater reliabilitydecreased sensitivity and inter-rater reliability

Shlipak MG, Lyons WL, Go AS et al. Should the Shlipak MG, Lyons WL, Go AS et al. Should the electrocardiogram be used to guide therapy for patients electrocardiogram be used to guide therapy for patients with left bundle-branch block and suspected myocardial with left bundle-branch block and suspected myocardial infarction? Jama 1999; 281 (8):714-9.infarction? Jama 1999; 281 (8):714-9.

Edhouse JA, Sakr M, Angus J et al. Suspected myocardial Edhouse JA, Sakr M, Angus J et al. Suspected myocardial infarction and left bundle branch block: infarction and left bundle branch block: electrocardiographic indicators of acute ischaemia. J electrocardiographic indicators of acute ischaemia. J Accid Emerg Med 1999; 16 (5):331-5.Accid Emerg Med 1999; 16 (5):331-5.


Prominent Prominent Electrical Forces Electrical Forces

Left Ventricular Left Ventricular HypertrophyHypertrophy

ECG Diagnostic Criteria ECG Diagnostic Criteria for LVHfor LVH

SensitivSensitivityity

SpecificSpecificityity

Sokolow-Lyon IndexSokolow-Lyon Index

SV1 + (RV5 or RV6)>35mmSV1 + (RV5 or RV6)>35mm2222 100100

Cornell Voltage CriteriaCornell Voltage Criteria

SV3+RaVL>28 mm (men), SV3+RaVL>28 mm (men), 20mm(women)20mm(women)

4242 9696

R1 + SIII>25 mmR1 + SIII>25 mm 1111 100100

R in aVL> 11mmR in aVL> 11mm 1111 100100Other Criteria include Romhilt and Estes Point Score System

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.

The initial upsloping of the elevated The initial upsloping of the elevated ST segment is frequently ST segment is frequently concave concave in LVH in LVH as opposed to the more as opposed to the more likely flat/convex ST segment likely flat/convex ST segment elevation in ACSelevation in ACS

The T wave is usually asymmetrical asymmetrical in LVHin LVHas opposed to the symmetrical T wave seen in coronary ischemia

ECG Changes of Left ECG Changes of Left Ventricular Hypertrophy vs Ventricular Hypertrophy vs

AMIAMI

ConclusionConclusion

Not all STE are due to STEMINot all STE are due to STEMI ECG remains a good diagnostic tool, ECG remains a good diagnostic tool,

but must be correlated with clinical but must be correlated with clinical history and physical examinationhistory and physical examination

Certain characteristics of the ECG Certain characteristics of the ECG changes may aid in the correct changes may aid in the correct diagnosis: morphology, distribution, diagnosis: morphology, distribution, associated QRS complexes, voltage associated QRS complexes, voltage forces, etc.forces, etc.

ReferencesReferences

Wang K, Asinger RW, Marriott HJ. Wang K, Asinger RW, Marriott HJ. ST-segment elevation in conditions ST-segment elevation in conditions other than acute myocardial other than acute myocardial infarction. N Engl J Med 2003; 349 infarction. N Engl J Med 2003; 349 (22):2128-35.(22):2128-35.

Chan TC, Brady WJ, Harrigan RA et Chan TC, Brady WJ, Harrigan RA et al. ECG in Emergency Medicine and al. ECG in Emergency Medicine and Acute Care. 1st ed. Pennsylvania: Acute Care. 1st ed. Pennsylvania: Elsevier Mosby; 2005.Elsevier Mosby; 2005.

ReferencesReferences Goldberger: Clinical Electrocardiography: A Goldberger: Clinical Electrocardiography: A

Simplified Approach, 6th edition, 1999.Simplified Approach, 6th edition, 1999. William J. Brady, Theodore C. Chan. William J. Brady, Theodore C. Chan.

Electrocardiographic Manifestations: Electrocardiographic Manifestations: Benign Early Repolarization. The Journal of Benign Early Repolarization. The Journal of Emergency Medicine, Vol. 17, No. 3, pp. Emergency Medicine, Vol. 17, No. 3, pp. 473–478, 1999473–478, 1999

Sgarbossa EB, Pinski SL, Barbagelata A, et Sgarbossa EB, Pinski SL, Barbagelata A, et al. Electrocardiographic diagnosis of evolv-al. Electrocardiographic diagnosis of evolv-ing acute myocardial infarction in the ing acute myocardial infarction in the presence of left bundle-branch block. N presence of left bundle-branch block. N Engl J Med 1996; 334:481-7.Engl J Med 1996; 334:481-7.

ST Segment Elevations in ECG

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