EKGsThe Basics for FP Residents

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EKGsThe Basics for FP Residents

• Jess Fogler, MD
• University of California, San Francisco

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Part II

• Hypertrophy
• Ischemia
• Misc.

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Train your eyes

• Train your eyes for Rate
• Check the computer
• Train your eyes for Rhythm
• Check the rhythm strip
• Check I, II, avF
• Train your eyes for Axis
• Check I, II
• Train your eyes for Intervals
• PR check II
• QT check the computer
• QRS check I, V1

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• Hypertrophy
• Ischemia
• Misc.

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Hypertrophy

• Get a cheat sheet and use it!
• Read the computerits good at measuring things!

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Left Ventricular Hypertrophy

• An approach
• 1. Start with aVL
• R aVLgt9mmwomen or 11mmmen
• 2. Then look at V3
• R aVL S V3 gt20mmwomen or 25mmmen

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Left Ventricular Hypertrophy

• LVH with strain
• ST and T opposite to main QRS in all leads
• Except in transitional leads!
• Asymmetric sloping of ST segment
• Starts subtly with T wave flattening

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Train your eyes

• Train your eyes for LVH
• Look atin order
• avL
• V3
• Read the computer
• Check your cheat sheet

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• Hypertrophy
• Ischemia
• Misc.

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Myocardial Ischemia/Infarction

• Anatomy
• 3 main coronary arteries
• RCA RV and inferior portion of LV
• LAD ventricular septum and most of LV free wall
• LCx lateral wall, posterior LV

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Evolution of EKG Changes

• Ischemia
• Prolonged QT
• Tall T waves
• T wave inversion
• Injury
• Subendocardial ST depression
• Subepicardial/transmural ST elevation

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Subendocardial Injury

Current of injury directed towards the middle of
the heart Seen as ST depression by leads that
view that area
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Transmural Injury
Current of injury directed away from the
heart. Seen as ST elevation by leads that view
that surface

Seen as ST depression by leads opposite
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Evolution of EKG Changes

• Infarct
• Pathologic Q waves
• Later, inverted T waves
• Over time
• Qs can be lost
• 30 lost in 3 months
• ST segment elevation resolves
• T wave inversion may or may not persist
• Nonspecific ST-T abnormalities

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EKG Diagnosis of MI

• How sensitive is the EKG for diagnosis of MI?
• Multicenter Chest Pain Study prospective study
  of 1024 pts with documented MI
• Rouan et al. Am J Cardiol (1989)

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EKG Diagnosis of MI

• 1. Examine T waves, ST segments, QRS for signs of
  ischemia, injury, infarction
• 2. Characterize the location and the extent of
  the insult
• 3. Determine the age of the insult

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EKG Diagnosis of MI

• 1. Look for signs of ischemia/injury
• T wave changes
• Flattening, inversion
• Tall T waves
• ST elevation
• indicates primary area
• 1 mm in at least two anatomically contiguous
  leads
• ST depression
• Subendocardial injury
• Reciprocal change

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EKG Diagnosis of MI

• Two areas of special concern
• Posterior injury
• Will only show reciprocal changes on a standard
  12 lead EKG
• ST depression or R waves leads V1-3

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EKG Diagnosis of MI

• Two areas of special concern
• Right ventricle injury
• Best assessed with right sided leads
• A complication of inferior infarct (19-43)
• Clinically important
• Best criterion
• ST elevation in V4R

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EKG Diagnosis of MI

• Examine QRS for signs of infarction
• Poor R wave progression
• Loss of R wave height across precordial leads
• Normal R wave height increases V1 - V5 with V5 gt
  V6

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EKG Diagnosis of MI
Examine QRS for signs of infarction Poor R
wave progression Loss of R wave height across
precordial leads Normal R wave height increases
V1 - V5 with V5 gt V6
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EKG Diagnosis of MI

• 2. Locate the insult
• Anterior (39)
• ST elevation in leads V1-4
• Inferior (57)
• ST elevation in leads II, III, aVF
• Apical/lateral
• ST elevation in leads V5-6 or I, aVL
• Posterior
• ST depression leads V1-3 (reciprocal changes)
• Right Ventricle
• ST elevation in V4R

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EKG Diagnosis of MI

• 4. Determine the age of the insult
• Ischemia T wave changes
• Acute injury
• ST elevation and peaked T waves
• Acute infarct
• Pathologic Q waves
• Inverted T waves
• Old infarct
• Possibly Qs
• Possibly T wave inversion
• Non-specific ST-T changes

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Train your eyes

• Train your eyes for MI
• Look at all T waves
• Look at all ST segments
• Check for Q waves
• Check for R waves in V1-2

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Train your eyes

• Train your eyes for Rate
• Check the computer
• Train your eyes for Rhythm
• Check the rhythm strip
• Check I, II, avF
• Train your eyes for Axis
• Check I, II
• Train your eyes for Intervals
• PR check II
• QT check the computer
• QRS check I, V1

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Train your eyes

• Train your eyes for LVH
• Look atin order
• avL
• V3
• Check your cheat sheet
• Read the computer
• Train your eyes for MI
• Look at all T waves
• Look at all ST segments
• Check for Q waves
• Check for R waves in V1-2