ECG%20Review:%20The%20Basics

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ECG Review The Basics

• Megan Chan, PGY-1
• UHCMC 2015

http//thepracticalpsychosomaticist.com/2013/04/01
/qtc-interval-prolongation-and-antipsychotics-by-e
lysha-elson-pharm-d-mph/
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The Basics
http//flylib.com/books/en/2.569.1.27/1/
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The ECG Unit
http//cal.vet.upenn.edu/projects/lgcardiac/ecg_tu
torial/printerval.htm
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The Systematic Process

• Rate
• 300/( large boxes between RR interval)
• 300-150-100-75-60-50
• Rhythm
• Regular vs irregular
• Sinus rhythm?
• P before every QRS (easiest to see in leads II
  and V1)
• Positive p wave in I II negative p in aVR
• Axis
• Normal axis?
• Positive QRS sum in I and II (or aVF )
• Left deviation?
• Up in I, down in II
• Right deviation?
• Down in I, up/down in II

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The Systematic Process Cont.

• Intervals
• PR interval normal 120-200ms (3-5 small boxes)
• Short PR interval WPW
• Long PR interval heart block
• QRS complex normal lt120ms ( 3 small boxes)
• Long QRS conduction delays, hyperkalemia,
  ventricular rhythm
• QT interval normal 430 in men, 450 in
  females (less than RR/2)
• Long QT MI, myocarditis, hypocalcemia,
  hypothyroidism, subarachnoid hemorrhage,
  drugssotolol, amiodarone, hereditary

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The Systematic Process Cont.

• Conduction Abnormalities
• AV blocks
• RBBB
• LBBB
• IVCD (interventricular conduction delay)
• Left Anterior Fascicular Block
• Left Posterior Fascicular Block

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http//healthybeatinghearts.blogspot.com/2011/01/f
irst-week-with-new-pacemaker.html
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http//www.zuniv.net/physiology/book/images/11-13.
jpg
http//dualibra.com/wp-content/uploads/2012/04/037
8001/Part209.20Disorders20of20the20Cardiovas
cular20System/Section202.20Diagnosis20of20Car
diovascular20Disorders/221.htm
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http//www.emedu.org/ecg/crapsanyallans.php
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Hemi Blocks Left Fascicular Blocks
http//www.usfca.edu/fac-staff/ritter/Image74.gif
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LAFB
LPFB
http//aliem.com/wp-content/uploads/2013/08/LAFB.p
ng
http//cdn.lifeinthefastlane.com/wp-content/upload
s/2011/02/avhisbb.jpg
http//aliem.com/wp-content/uploads/2013/08/LPFB.p
ng
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Hypertrophy
http//dualibra.com/wp-content/uploads/2012/04/037
8001/Part209.20Disorders20of20the20Cardiovas
cular20System/Section202.20Diagnosis20of20Car
diovascular20Disorders/221.htm
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The Systematic Process Cont.

• Chamber size

RAE LAE RVH LVH
Tall P gt 2.5 mm in lead II Large diphasic P with large initial phase in V1 Pgt 120ms Diphasic p with downward terminal phase gt 1mm wide and 1mm deep in V1 M-shaped P in I, II, or aVL R in aVR gt 5mm (or RgtQ) R in V1 gt 7mm qR in V1 R in V1 S in V5/V6 gt 10mm Deep S in V5/V6 gt 7mm R in aVL gt 11mm R in V5/V6 S in V1/V2 gt 35mm R in I S in III gt 25 mm R in aVF gt 20mm S in aVR gt 14mm
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The Systematic Process Cont.

• Ischemia
• What ECG changes do you expect to see?
• Hyperacute T waves ? Inverted T waves ? ST
  segment elevation ? Q waves
• ST depressions ???
• Subendocardial ischemia
• ST elevations ???
• Transmural ischemia
• What are Pathologic Q waves?
• 1 small box wide and/or gt5mm or 1/3 of R wave
  deep
• Other changes
• Old septal infarct No R waves in V1-V3
• Old lateral infarct No R wave progression in
  V4-V6
• RV infarct ST elevation in V4 V5 with right
  sided EKG

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The Systematic Process Cont.

• Everything Else
• Pericardial Effusion
• Low voltage (R waves lt 5mm in limb leads, lt10mm
  in precordial leads)
• Pericarditis
• Diffuse ST elevations and PR depressions
• Pulmonary Embolism
• S1Q3T3S wave in I, Q wave in III, T wave
  inversion in III

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Location Leads Occluded Vessel
Anterior V2-V4 LAD
Anteroseptal V1-V4 LAD
Anterolateral V1-V6, I, aVL LAD, diagonal
Lateral V5-V6, I, aVL Circumflex, diagonal
Inferior II, III, aVF RCA, circumflex
Posterior Tall R in V1-V3, ST depression in V1-V2 RCA
http//www.edoctoronline.com/media/19/photos_245a9
75b-66ad-4f7e-86d8-82d3ca7d0120.jpg
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http//dotwordpressdotcom.wordpress.com/med-school
/clinical-skills/ecgs/
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THE DR. ORTIZ METHOD

• 4 step method to interpreting 80 of ECGs in 1
  minute
• What are the most important ECG leads?
• II best axis, dx inferior wall MI, most studied
• V1best p wave, dx anterior wall MI RBBB
• V5dx lateral wall MI, LBBB, LVH
• What 2 leads are best for determining axis?
• I II
• 100 sensitive specific w/ zero false
• Normal axis is -30 to 90
• aVF was used gt 100 years ago
• Special thanks to Dr. Jose Ortiz!

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THE DR. ORTIZ METHOD

• Step 1 Demographics
• Verifying pt name and calibration of ECG
• Step 2 Two second look at lead II
• Regularity of the tracing. Any funny beats?
• P waves
• Upright ? sinus
• M shape ? LAE
• Mountain peaks ? RAE
• Axis QRS positive ? 50 chance of normal axis
• Intervals
• Normal QRS lt3 boxes
• gt3 boxes BBB
• Q waves 75 risk for inferior MI

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THE DR. ORTIZ METHOD

• Step 3 Study three things about the QRS
• Axis normal vs L deviation vs R deviation
• Confirm suspected axis by looking at lead I
• Width normal vs RBBB vs LBBB
• gt 3 boxes wide abnormal
• Look at V1 ? If RSR then RBBB If large S then
  LBBB.
• Height normal vs low voltage vs LVH
• Remember 14-12-35 for LVH
• Lead I R gt 14
• Lead aVL R gt 12
• S in V1 R in V5/V6 gt 35

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THE DR. ORTIZ METHOD

• Step 4 Rate, ST segments, T waves, Infarcts
• Anterior/Septal infarct V1-V4
• Inferior infarct II, III, aVF
• Lateral infarct aVL, I, V5, V6

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Draw A Normal ECG
http//www.lysosomalstorageresearch.ca/Fabry_eClin
ic/electrocardiography-ecg.html
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How To Draw A Normal ECG
aVR
V4
I
V1
Same as aVR but T P waves can be or
Similar to V3 with smaller S, taller R
Same as II
Inverted II
aVL
V2
II
V5
Similar to V3 but less QRS voltage
Similar to V3 with larger S, smaller R
Similar to V4 with smaller S, taller R (R wave
progression)
aVF
III
V3
V6
Same as II
Same as II
Same as II
Biphasic QRS
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REFERNCES

• Agabegi SS, Agabegi ED. Step up to Medicine, 3rd
  ed. 2013. Lippincott Williams Wilkins.
  Philadelphia, PA.
• Gomella LG, Haist SA. Basic EKG reading. In
  Clinicians Pocket Reference. McGraw-Hill 2007.
  http//flylib.com/books/en/2.569.1.27/1/.
  Accessed Nov 18, 2014.
• Longo DL, Fauci AS, Kasper DL, et al.
  Electrocardiography. In Harrisons Principles of
  Internal Medicine, 18th ed. 2012. McGraw Hill.
  New York, NY.
• University of Illinois at Chicago. Online ICU
  Guidebook. 2013. http//chicago.medicine.uic.edu/U
  serFiles/Servers/Server_442934/Image/1.1/residentg
  uides/final/icuguidebook.pdf. Accessed December
  1, 2014.