AMI/ACS Dx: Old EKG

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AMI/ACS Dx Old EKG

• When comparing to an old EKG, the old EKG should
  not be one done in the ED at the time of the
  acute presentation for AMI/ACS
• The goal is to establish no change as compared to
  baseline, non-ischemia EKG, eg LVH with strain
  pattern

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EKG Diagnosis LVH with Strain Pattern

• LVH criteria, ST-T wave changes

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Diagnosis ECG Monitoring

• Dysrhythmias
• Bradycardia
• Heart blocks
• Malignant ventricular ectopy
• Ventricular Fibrillation

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Bifascicular Block

• RBBB Opposite T waves normal

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Non-sustained VT in AMI
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Non-sustained VT in AMI
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AMI/ACS DiagnosisCardiac Enzymes
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AMI/ACS Lab Evaluation
Marker Elevation Peak Duration
Myoglobin 1-4 h 6 h 24 h
Troponin I 3-12 h 18 h 5-10 days
Troponin T 3-12 h 12 h 5-14 days
CK-MB 3-12 h 18-24 h 2 days
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Cardiac Enzymes CPK-MB

• CPK-MB
• Sensitive and specific
• Limited potential for early diagnosis??
• Two hour change in CK-MB may be accurate to
  predict ACS

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Cardiac Enzymes Myoglobin

• Myoglobin
• Sensitive but not specific
• Not used to rule out clinically
• Peaks earlier than CPK
• Limited utility given ability to use CK-MB and
  troponin

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Cardiac Enzymes Troponins

• Troponins true cardiac markers
• Touted to be highly specific
• More sensitive than CPK-MB at detecting small
  infarcts
• Elevation predicts ? mortality and complications
• Troponin T less specific than troponin I

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Cardiac Enzymes Troponins

• Troponins
• Can troponin be positive without ACS?
• What is the significance of isolated troponin
  elevation with neg EKG?
• Cannot overlook higher complication rate if
  troponin positive

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AMI/ACS DiagnosisOther Acute Tests
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AMI/ACS Diagnosis CXR

• CM, CHF
• Other causes of chest pain
• Pneumothorax, rib fractures
• Pneumonia
• Aortic dissection
• Carcinoma

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AMI/ACS Diagnosis CXR

• Acute pulmonary edema

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AMI/ACS Diagnosis Echocardiography

• What are the indications for echocardiography in
  the ED?
• How might this data alter the acute management of
  an STEMI patient?

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AMI/ACS Diagnosis Echocardiography

• Uncertain ACS diagnosis
• Uncertain need for acute PCI
• LV dysfunction suggests more gravely ill AMI
  patient
• Valvular dysfunction

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AMI/ACS Diagnosis Echocardiography

• Sensitive in detecting regional wall motion
  abnormalities
• Cannot differentiate between ischemia, AMI, or
  old MI
• Can detect valve stenosis, regurgitation,
  insufficiency

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AMI/ACS Diagnosis Echocardiography
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AMI/ACS Diagnosis Stress Testing

• Measures inducible ischemia
• Must rule out AMI/ACS first
• Physical, process limitations
• Stress thallium may be needed
• Accuracy, utility can vary
• Part of a chest pain protocol

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AMI/ACS Diagnosis Stress Testing

• Persantine stress test
• In general, thallium clears more slowly from
  regions supplied by stenotic vessels than from
  normal myocardial regions. Areas of significant
  hypoperfusion will have very slow clearance and
  may even accumulate thallium.

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AMI/ACS Diagnosis Sestamibi (Cardiolyte) Scanning

• Technetium
• Measures focal ischemia
• Pain for at least 1 hr or ongoing
• Resolution within 30 min only
• Poor perfusion, no uptake
• May lead to early catheterization
• Part of a chest pain protocol

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AMI/ACS Diagnosis Sestamibi (Cardiolyte) Scanning

• Myoview ( technetium Tc-99m tetrofosmin )
• A cardiac imaging agent, is useful in the
  diagnosis and localization of regions of
  reversible myocardial ischemia in the presence or
  absence of infarction under exercise and rest
  conditions.

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AMI/ACS DiagnosisChest Pain Protocols
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AMI/ACS Diagnosis Chest Pain Protocols

• Low risk population
• Serial EKGs
• Serial cardiac enzymes
• Provocative testing as needed
• Detects AMI, ACS
• Identify uncomplicated patients

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AMI/ACS Diagnosis Chest Pain Protocols

• The Erlanger chest pain evaluation protocol a
  one-year experience with serial 12-lead ECG
  monitoring, two-hour delta serum marker
  measurements, and selective nuclear stress
  testing to identify and exclude acute coronary
  syndromes.
• Fesmire F Ann Emer Med 2002
• CONCLUSION An accelerated chest pain evaluation
  strategy consisting of SECG, 2-hour delta serum
  marker measurements, and selective nuclear stress
  testing in conjunction with physician judgment
  identifies and excludes MI and 30-day ACS during
  the initial evaluation of patients with chest
  pain.

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AMI/ACS Diagnosis Chest Pain Protocols

• Delta creatine kinase-MB outperforms myoglobin at
  two hours during the emergency department
  identification and exclusion of troponin positive
  non-ST-segment elevation acute coronary
  syndromes.
• Fesmire F Ann Emer Med 2004
• CONCLUSION A 2-hour delta CK-MB level
  outperforms myoglobin level in the early
  identification and exclusion of acute myocardial
  infarction in non-ST-segment elevation chest pain
  patients. This finding suggests that myoglobin
  may no longer be the optimal early marker of
  acute myocardial infarction when troponins are
  used as the criterion standard.

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AMI/ACS DiagnosisGuidelines
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AMI/ACS Rx Guidelines

• What guidelines guide AMI Rx?
• How are these guidelines derived? How are they
  stated

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ACEP AMI/ACS Guidelines

• Ann Emer Med, 2000
• Standards, guidelines, options
• Criteria emergent reperfusion Rx
• PTCA within 120 minutes
• Options for serial enzymes

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AMI/ACS Diagnosis Clinical Guidelines

• Low risk population
• Serial EKGs
• Serial cardiac enzymes
• Provocative testing as needed
• Detects AMI, ACS
• Identify uncomplicated patients

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AMI/ACS Diagnosis Conclusions

• Important clinical disease state
• Risk stratification key
• Diagnosis can be made
• Most tests acutely available
• A protocol assists in diagnosis

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AMI/ACS DiagnosisQuestions?

• www.acc.org or www.americanheart.org
• www.acep.org
• www.guidelines.gov
• PDF file allows for optimal printing
• edsloan_at_uic.edu [phone]

ami acs icep part 1 modified 2007