ST ELEVATION - Calgary Emergency Medicine
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Transcript ST ELEVATION - Calgary Emergency Medicine
ST ELEVATION
Jason 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 – V4
Septal: V1 – V2
LAD
II, III, aVF
Lateral
I, aVL, V5, V6
LAD
RCA
Circumflex
III, aVF, V1
Inferior
II, III, aVF
RCA (80%)
Circumflex (15%)
Both (5%)
aVL, I
Posterior
V1 – V3
(Depression)
RCA
Circumflex
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
Engl J Med. 2009 Dec 24;361(26):2529-37.
with early repolarization on electrocardiography. N
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
Criterion
Score
Concordant ST Elevation ≥ 1mm, any lead
5
ST Depression ≥ 1mm, V1-V3
3
Discordant ST Elevation ≥ 5mm, any lead
2
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.
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