Leanna R. Miller, RN, MN, CCRN-CSC, PCCN-CMC, CEN, CNRN, CMSRN, NP

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ST Segment Changes Identifying MI Mimics

• Leanna R. Miller, RN, MN, CCRN-CSC, PCCN-CMC,
  CEN, CNRN, CMSRN, NP
• Education Specialist
• LRM Consulting
• Nashville, TN

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Place Your Phone Beeper on Silence!!!
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ST Segment Changes Identifying MI Mimics

• Objectives
• Evaluate common abnormalities that mimic
  myocardial infarction.
• Identify the criteria for pericarditis and
  evidence based interventions.
• Differentiate between pulmonary embolus and
  myocardial infarction using diagnostic criteria.

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ST Segment Changes Identifying MI Mimics

• Acute Coronary Syndromes
• Unstable Angina
• Non ST segment Elevation MI (NSTEMI)
• ST segment Elevation MI (STEMI)

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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics

• Acute Coronary Syndromes
• Clinical Symptoms
• typical
• atypical

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ST Segment Changes Identifying MI Mimics

• Acute Coronary Syndromes
• Diagnostics
• Echocardiography
• Lab
• ABGs
• H H
• enzymes

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ST Segment Changes Identifying MI Mimics

• Acute Coronary Syndromes
• Diagnostics
• ECG (12 or 15 lead)
• T wave inversion
• ST segment elevation
• Q wave
• reciprocal ST segment
• depression

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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
SITE INDICATIVE RECIPROCAL
Septal V1, V2 None
Anterior V2, V3, V4 None
Anteroseptal V1, V2, V3, V4 None
Lateral I, aVL, V5, V6 II, III, aVF
Anterolateral I, aVL, V3, V4, V5, V6 II, III, aVF
Inferior II, III, aVF I, aVL, V2, V3
Posterior None V1, V2
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
Variation to ST Segment Elevation
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics

• High acute risk factors for progression to
• myocardial infarction or death
• recurrent chest pain at rest
• dynamic ST-segment changes ST-segment depression
  gt 0.1 mV or transient (lt30 min) ST-segment
  elevation gt0.1 mV
• elevated Troponin-I, Troponin-T, or CK-MB levels

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ST Segment Changes Identifying MI Mimics

• High acute risk factors for progression to
• myocardial infarction or death
• hemodynamic instability within the observation
  period
• major arrhythmias (ventricular tachycardia,
  ventricular fibrillation)
• early post-infarction unstable angina
• diabetes mellitus

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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics

• Acute Pericarditis
• Introduction
• causes physical discomfort
• predisposition to tachydysrhythmias

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ST Segment Changes Identifying MI Mimics

• Acute Pericarditis
• ECG Criteria
• ST segment elevation
• PR segment depression
• T wave flattening or inversion
• atrial dysrhythmias

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ST Segment Changes Identifying MI Mimics

• Acute Pericarditis
• ST segment elevation
• not isolated or discrete segments
• upward concavity
• may be notching at the junction of
• QRS and ST segment
• no reciprocal ST segment depression

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ST Segment Changes Identifying MI Mimics

• Acute Pericarditis
• PR interval
• interval between end of P wave and
• beginning of QRS may be depressed
• most often seen in lead II and V
• leads may be only ECG finding

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ST Segment Changes Identifying MI Mimics

• Acute Pericarditis
• T wave flattening or inversion
• no T wave inversion during acute phase
• uncomplicated pericarditis negative
• T waves only occur in leads which usually
• have negative T waves (aVR V1)

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ST Segment Changes Identifying MI Mimics

• Acute Pericarditis
• Atrial dysrhythmias
• SVT in postoperative open heart patient
• treat with low dose steroids

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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics

• Acute Pericarditis
• Complications (pericardial effusion)
• dampening of electrical output
• low voltage in all leads
• ST segment T wave changes

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ST Segment Changes Identifying MI Mimics

• Acute Pericarditis
• Complications (pericardial effusion)
• freely rotating heart produces
• electrical alternans

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ST Segment Changes Identifying MI Mimics

• Dresslers Syndrome
• Introduction
• postmyocardial infarction syndrome
• autoimmune process

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ST Segment Changes Identifying MI Mimics

• Dresslers Syndrome
• Clinical Presentation
• low grade fever
• chest pain (worsens with deep
• breath lessens with sitting up
• and leaning forward)
• pericardial friction rub

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ST Segment Changes Identifying MI Mimics

• Dresslers Syndrome
• 12 lead ECG
• diffuse ST segment elevation across the
  precordial leads

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ST Segment Changes Identifying MI Mimics

• Dresslers Syndrome
• Treatment
• corticosteroid administration
• monitor for complications (effusion)

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ST Segment Changes Identifying MI Mimics

• Pulmonary Embolus
• Introduction
• sudden massive PE produces ECG changes
• must get 12 lead to rule out MI

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ST Segment Changes Identifying MI Mimics

• Pulmonary Embolus
• ECG Findings
• RVH with strain
• RBBB pattern in V1
• large S wave in Lead I large Q wave in Lead
• III (S1Q3 pattern)

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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics

• Ventricular Aneurysm
• Introduction (etiology)
• myocardial infarction
• congenital
• cardiomyopathy
• inflammatory
• idiopathic

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ST Segment Changes Identifying MI Mimics

• Ventricular Aneurysm
• Introduction
• infereolateral wall of LV
• symptoms include CHF exercise
• induced syncope (VT)

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ST Segment Changes Identifying MI Mimics

• Ventricular Aneurysm
• ECG Findings
• persistent ST segment elevation
• small q wave in II, III, aVF
• sustained VT with RBBB morphology

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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics

• Ventricular Aneurysm
• Treatment
• surgical resection
• antidysrhythmics
• anticoagulants
• treat heart failure
• ablation therapy

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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics

• Left Bundle Branch Block (LBBB)
• QRS duration gt 0.12 second
• absence of septal q waves and S wave
• in I, aVL, V5 6 ( complex usually
• notched)
• broad QS or rS in V1 3 (- complex)

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ST Segment Changes Identifying MI Mimics

• Left Bundle Branch Block (LBBB)
• S T, T wave changes in leads I,
• aVL V5 6 (T wave opposite QRS)
• delayed intrinsicoid deflection over
• left ventricle (V6) normal over V1

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ST Segment Changes Identifying MI Mimics

• Left Bundle Branch Block (LBBB)
• hypertensive heart disease
• aortic stenosis
• degenerative changes of the conduction
• system
• coronary artery disease

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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
LBBB with Acute Myocardial Infarction
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ST Segment Changes Identifying MI Mimics
Left Ventricular Hypertrophy
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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
Left Ventricular Hypertrophy
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ST Segment Changes Identifying MI Mimics

• Brugada Syndrome
• autosomal dominant inheritance (SCN5A) gene
• sodium channel involvement in 25 of the patients
• Asian populations (58)
• high incidence of polymorphic ventricular
  tachycardias

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ST Segment Changes Identifying MI Mimics

• Brugada Syndrome
• found in right precordial leads
• prominent J wave
• ST segment elevation in the absence of
  structural heart disease
• three types

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ST Segment Changes Identifying MI Mimics

• Brugada Syndrome
• Type I ST segment elevation is triangular and
  T waves may be inverted in V1 V3
• Type II downward displacement of ST segment
  (does not reach baseline)
• Type III middle part of ST segment touches
  baseline

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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics
Brugada Syndrome
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ST Segment Changes Identifying MI Mimics

• LBBB
• Infarction Resemblance
• ST segment elevation in the negatively deflected
  leads, (V1 V3)
• QS complexes in the negatively deflected leads,
  (V1 V3)
• Recognition
• Wide QRS
• QS in V1

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ST Segment Changes Identifying MI Mimics

• Ventricular Rhythms
• Infarction Resemblance
• ST segment elevation in the negatively deflected
  leads, (V1 V3)
• QS complexes in the negatively deflected leads,
  (V1 V3)
• Recognition
• Wide QRS following pacer spike
• Negative V1 (RV paced)

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ST Segment Changes Identifying MI Mimics

• LVH
• Infarction Resemblance
• ST segment elevation in the negatively deflected
  leads, (V1 V3)
• Recognition
• Choose deepest S wave from V1 and V2
• Choose tallest R wave from V5 and V6
• Add deflections of tallest R wave and deepest S
  wave
• Suspect LVH if total is gt 35

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ST Segment Changes Identifying MI Mimics

• Pericarditis
• Infarction Resemblance
• ST segment elements in multiple leads
• Recognition
• ST segment elevation not in anatomical grouping
• PR segment depression
• Notching of the J point

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ST Segment Changes Identifying MI Mimics

• Acute Pulmonary Emboli
• Infarction Resemblance
• RVH with strain pattern
• RBBB pattern in V1
• S1Q3 on frontal plane
• Recognition
• Patient is symptomatic with atypical cardiac pain
• Elevated BMP
• r/o with spiral CT/angiogram

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ST Segment Changes Identifying MI Mimics

• Ventricular Aneurysm
• Infarction Resemblance
• High risk for ventricular dysrhythmias (VT with
  RBBB pattern)
• Inferolateral MI
• Persistent ST segment elevation
• Small q wave in II, III, aVL
• Recognition
• Structural abnormality on ECHO
• CHF exercise induced syncope (VT)

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ST Segment Changes Identifying MI Mimics

• Brugada Syndrome
• Infarction Resemblance
• Ventricular dysrhythmias (polymorphic VT)
• ST segment elevation in right precordial leads
• Recognition
• Autosomal dominant
• Asian culture
• No structural abnormality noted on ECHO

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ST Segment Changes Identifying MI Mimics

• Prominent J with ST segment elevations
• septal MI
• RV cardiomyopathy
• pericardial effusion
• hypercalcemia

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ST Segment Changes Identifying MI Mimics

• Prominent J with ST segment elevations
• hyperkalemia
• acute pulmonary embolism
• subarachnoid hemorrhage
• tricyclic antidepressant intoxication

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ST Segment Changes Identifying MI Mimics
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ST Segment Changes Identifying MI Mimics

• In Conclusion
• is the patient having a MI?
• a variety of conditions can mimic infarction
• ST segment changes