ST ELEVATION - Calgary Emergency Medicine

Report
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

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