CMC ECG MASTERS
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  • Basics
  • P Waves
    • Sinus
    • Not sinus
    • Absent
  • PR interval
    • Short PR
    • Prolonged PR
    • Variable PR
  • QRS
    • Wide
    • Axis >
      • LAD
      • RAD
    • Amplitude >
      • High Voltage
      • Low Voltage
      • Alternans
    • R Wave Progression
    • Pathological Q waves
  • ST Segments
    • ST Elevation
    • ST Depression
  • T Waves
    • Flat, Bifid, or Notched
    • Inverted
  • QT intervals
    • Prolonged QT
    • Short QT
  • Patterns
    • STEMI
    • Pulmonary Embolism
    • Ventricular Hypertrophy
    • Pulmonary Disease
    • ST-T Patterns
    • Electrolyte Abnormalities
    • Cases >
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  • Interpreter

STEMI

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Picture
Time course of ECG progression
  • ​Variable; phases may be skipped
  • ECG progression is modified by reperfusion therapy
ECG Leads
 Location of MI
Probable Culprit
II, III, aVF (±V5,V6)
Inferior
RCA (or dominant LCX)
Mirror image V1-V2 (R­, ST¯, T­)
Posterolateral
LCX
II-III-aVF, plus V1 and RV4
Inferior + RV
Proximal RCA
V1-V4
Anteroseptal
LAD
V1-V6 (± I, aVL)
Extensive Anterior
LAD
I, aVL, V4-V6  ​
Lateral
LCX
I, aVL, V2 (± mirror image III)
High Lateral
LAD-D1

FREQUENTLY MISSED MIs
Posterolateral (LCX)
  • Almost always due to LCX occlusion, accounts for 10-15% of all STEMIs and is the most frequently missed
  • ST depression but upright T waves in V1-V3 (diff dx: ant. ischemia or posterolateral STEMI)
  • Later: increased R/S ratio in V1-V2
  • Frequently accompanied by small Q waves or T-wave inversion in inferior or lateral leads
  • If you suspect posterior MI, place additional electrodes
    • V7 posterior axillary
    • V8 tip of the scapula
    • V9 left paraspinal line
  • Frequently associated with ischemia or infarction of the posterior papillary muscle
  • May result in mitral regurgitation
Picture
Picture
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ST Depression in V1-V4, subtle ST Elevation in I, aVL
High lateral
  • Second most frequently missed MI, rare and usually small
  • Typically LAD-D1
  • Subtle ST in aVL, V2, sometimes in I
  • Mirror image (QRS, ST and T) in lead III
  • "South African Flag" sign
  • If you suspect high lateral MI, move V4, v5, V6 up one intercostal space
Picture
RV infarct
  • Almost always in association with inferior MI
  • ST in R-sided chest leads; sometimes in V1; rarely in V1-V4 (may mimic anterior STEMI)
  • Combination of ST in inferior leads plus ST in V1 is highly specific for RV infarct
  • Frequently associated with sinus bradycardia or atrial fibrillation with AV block
Anterior “STEMI” without ST elevation
  • J-point depression followed by upsloping STs in the anterior chest leads
  • Very tall (“hyperacute”) T waves usually taller than the corresponding QRS complexes
DeWinter's Sign
  • Proximal LAD occlusion
  • 1-3 mm upsloping ST depression at the J point in V1-V6
  • Tall, positive symmetrical T waves
  • Ts may be taller than R waves
  • Slight ST elevation in aVR
  • Patients frequently young males
  • No distinct anatomic pattern of CAD
Picture
Picture
Pulmonary Embolism
  • Home
    • About Us
    • EM GuideWire
    • CMC Ed Masters
    • Ped EM Morsels
  • Basics
  • P Waves
    • Sinus
    • Not sinus
    • Absent
  • PR interval
    • Short PR
    • Prolonged PR
    • Variable PR
  • QRS
    • Wide
    • Axis >
      • LAD
      • RAD
    • Amplitude >
      • High Voltage
      • Low Voltage
      • Alternans
    • R Wave Progression
    • Pathological Q waves
  • ST Segments
    • ST Elevation
    • ST Depression
  • T Waves
    • Flat, Bifid, or Notched
    • Inverted
  • QT intervals
    • Prolonged QT
    • Short QT
  • Patterns
    • STEMI
    • Pulmonary Embolism
    • Ventricular Hypertrophy
    • Pulmonary Disease
    • ST-T Patterns
    • Electrolyte Abnormalities
    • Cases >
      • Case 1
      • Case 2
      • Case 3
      • Case 4
      • Case 5
      • Case 6
      • Case 7
      • Case 8
      • Case 9
      • Case 10
      • Case 11
      • Case 12
      • Case 13
      • Case 14
      • Case 15
      • Case 16
      • Case 17
      • Case 18
      • Case 19
  • Interpreter