ST ELEVATIONJason Mitchell, PGY2

July 15, 2010

Context

CP and ST Elevation common ED presentation

Correct ECG interpretation impacts management decisions and patient outcome

Certain patients with CP and ST elevation require rapid intervention via thombolysis or PCI

Misdiagnosis potentially harmful

Context

1996 ACC/AHA Class I Recommendation for Thrombolysis

“ST elevation greater than 0.1 mV in two or more contiguous leads.”1

1 Ryan TJ, Anderson JL, Antman EM, et al. ACC/AHA guidelines for the management of patients with acute myocardial infarction. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Management of Acute Myocardial Infarction). .J Am Coll Cardiol. 1996 Nov 1;28(5):1328-428

Context

Disorders with ST Elevation Meeting ACC/AHA Thrombolysis Guideline

Acute Myocardial Infarction

Early Repolarization

Left Ventricular Hypertrophy

Left Ventricular Aneurysm

Left Bundle Branch Block Ventricular Paced Rhythm

Hypothermia (Osborn Waves)

Hyperkalemia

Brugada Syndrome Pulmonary Embolism

Acute Cerebral Hemorrhage

WPW

Context

2000 ACEP Qualifier “ST-segment elevations greater than 0.1 mV

in 2 or more contiguous leads that are not characteristic of early repolarization or pericarditis, nor of a repolarization abnormality from LVH or BBB in patients with clinical presentation suggestive of AMI.”2

2 Critical issues in the evaluation and management of adult patients presenting with suspected acute myocardial infarction or unstable angina. Ann Emerg Med 2000;35:521-525

ST Morphology

ST Morphology

Concave Up vs. Concave Down

ST Morphology

Concave Up vs. Concave Down

ST Segment Elevation

Differentiating STEMI from other ST Elevation Syndromes

Dynamic ECG changes

Reciprocal Changes

ST Morphology

STEMI Territories

Localizations

STEMI

STEMI

STEMI

STEMI

Location Leads Responsible Vessel(s)

Reciprocal Change

Anterior V1 – V4Septal: V1 –

V2

LAD II, III, aVF

Lateral I, aVL, V5, V6 LADRCA

Circumflex

III, aVF, V1

Inferior II, III, aVF RCA (80%)Circumflex

(15%)Both (5%)

aVL, I

Posterior V1 – V3(Depression)

RCACircumflex

II, III, aVF

Context

2000 ACEP Qualifier “ST-segment elevations greater than 0.1 mV

in 2 or more contiguous leads that are not characteristic of early repolarization or pericarditis, nor of a repolarization abnormality from LVH or BBB in patients with clinical presentation suggestive of AMI.”2

2 Critical issues in the evaluation and management of adult patients presenting with suspected acute myocardial infarction or unstable angina. Ann Emerg Med 2000;35:521-525

Early Repolarization

Early Repolarization

Normal variant Males > Females ECG Findings:

Diffuse, Concave up ST Elevation 2-5mm (Usually precordial)

Notched J-Point Prominent T-Waves Temporal stability

Early Repolarization

“Benign” Early Repolarization Increased prevalence of early repolarization in

idiopathic VF Most pronounced with inferior J-Point elevation

Increased risk of cardiac death (ie – sudden arrythmia) J-Point 1mm: RR 1.28, 95% CI 1.05 – 1.59 J-Point 2mm: RR 2.98, 95% CI 1.85 – 4.923

Isolated BER in limbs leads should prompt ACS investigations

3 Tikkanen JT, Anttonen O, Junttila MJ, et al. Long-term outcome associated with early repolarization on electrocardiography. N Engl J Med. 2009 Dec 24;361(26):2529-37.

Pericarditis

Pericarditis

Diffuse ST Elevation Diffuse PR Depression Caveat: aVR

ST Depression, PR Elevation

Pericarditis

Stages – All 4 Present in ~50% of patients I – ST Elevation, concordant T-Waves, PR

Depression

II – ST segments return to baseline, T-Waves flatten

III – T-Wave inversion

IV – T-Wave resolution

Pericarditis

Differentiation from STEMI Concave Up ST segments ST elevation beyond contiguous leads No simultaneous T-Wave inversion Reciprocal changes absent Serial ECGs not consistent with STEMI

patterns No Q-Wave development

Pericarditis vs. BER

Differentiation of Pericarditis from BER V6 ST/T Ratio

Pericarditis > 0.25 BER < 0.25

LVH

LVH

Tall R waves lateral leads Deep S waves anterior precordial leads Concave Up ST elevation, typically V1-V3 LAD

LBBB

LBBB

Wide QRS Large, positive R wave without q or s waves in I, aVL,

V6 Notched ‘M Shaped’ R wave V5, V6 Normal or leftward axis ST depression and T wave inversion in leftward leads ST elevation and upright T waves in right precordial

leads

LBBB

7% of MI4

Significantly less likely to receive ASA Increased in-hospital mortality

4 Go AS, Barron HV, Rundle AC, et al. Bundle-branch block and in-hospital mortality in acute myocardial infarction. National Registry of Myocardial Infarction. Ann Intern Med 1998 Nov 1;129(9):690-7.

LBBB

Sgarbossa Criteria5

Score ≥ 3 98% specific 20% sensitive6

5 Sgarbossa EB, Pinski SL, Barbagelata A, et al. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block. GUSTO-1 (Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries) Investigators. N Engl J Med 1996 Feb 22;334(8):481-7.6 Tabas JA, Rodriguez RM, Seligman HK, et al. Electrocardiographic criteria for detecting acute myocardial infarction in patients with left bundle branch block: a meta-analysis. Ann Emerg Med. 2008 Oct;52(4):329-336.e1.

Criterion ScoreConcordant ST Elevation ≥ 1mm, any lead

5

ST Depression ≥ 1mm, V1-V3 3Discordant ST Elevation ≥ 5mm, any lead

2

LBBB

LBBB

ECG Evolution Anterolateral MI

New S Waves in Leftward Leads I, aVL, V6

Anteroseptal MI Lateral q waves

I, aVL, V5-V6

RBBB?

Can present with ST elevation No impact on initial QRS vector

Q waves are not changed

Conclusion

Evaluate ECG in relation to clinical presentation

ST morphology Dynamic ECG changes, serial ECGs Look for reciprocal changes

Practice

Practice

Inferior MI V1 Elevation: RV Infarct ST Elevation III > ST Elevation II: RCA Occlusion

Practice

Practice

Hyperacute Anterior MI Note Mobitz II Conduction Block

Malfunctioning His-Pukinje system Suggests anterior occlusion Ie - LAD occlusion

Mobitz I Conduction Block Malfunctioning AV node Suggests ‘dominant’ coronary occlusion RCA or Circumflex

Practice

Practice

Posterior MI Note ‘q’ waves in anterior leads

Practice

Practice

WPW

Practice

Practice

LBBB Concerning for MI

Practice

Practice

Anterior MI