chapter page, 12-lead ecg for acute and critical care providers © 2006 by pearson education, inc....
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chapter
Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
6
Wide Complex Wide Complex TachycardiaTachycardia
Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Chapter 6 Objectives
• Describe the possible pitfalls in diagnosing wide complex tachycardia
• Describe the potential complications resulting from misdiagnosing WCT
• Describe four simple criteria for differentiating VT from SVT
• Identify VT vs. SVT on a series of 12-Leads
Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Pifalls in WCT
• Reliance on Lead II
• Reliance on the machine
• Vital signs/patient presentation
• Atrial fibrillation
• SVT is more common?
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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Machine Logic
Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Clinical Logic/Primary Survey
• Is the QRS >120 ms?
• Look at axis criteria (can be helpful)
• Look at the morphology in Leads V1 and V6
• Look for concordance (all up or all down)
• Is AV dissociation present?
• Patient history/meds
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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
First Criteria for VT
• Extreme right axis• Upright complex in V1 (MCL-1)• 99% diagnostic for VT
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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Example of VT63
Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Another Axis Criteria
• Right axis deviation
• Negative V1 (MCL-1)
• 90% specific for VT
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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Example: RAD + Negative V164
Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Morphology Clues to VT
• Lead V1 (MCL-1) with positive deflection• Taller left peak than right (a)• Steeple sign (single upright peak) (b)• Fireman’s hat (sloped) (c)• Each diagnostic of VT
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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Morphology Clues to VT
• Lead V1 (MCL-1) negative deflection
• Fat R wave (more that 40 ms wide) (a)
• Notch or slur to the initial downstroke (b or c)
Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Morphology Clues to VT
• Lead V6 (MCL-6)
• Predominately negative deflection in V6 indicates VT
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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Lead V6 Criteria65
Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Concordance
• All V-leads up or down
• All up: suggestive of VT but R/O WPW
• All down: suggestive of VT, R/O LBBB
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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Negative Concordance66
Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Positive Concordance WPW
• Best seen in Leads V3-V6, I, and aVL
• Delta waves diagnostic (slurred upstroke R wave)
• Short PR interval
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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
RS Interval
• Measure from the start of the R wave to the nadir point (tip) of the S wave
• RS >100 indicates VT
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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
A-Fib?
• Irregular rhythm
• Wide complexes can form during tachycardia
• Rate-dependent BBB
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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Capture or Fusion Beats
• Arrow on the 6th complex indicates an escape beat or fusion beat
• If seen it is diagnostic of VT (AV dissociation)
Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Patient History
• Two questions:• Have you had a
heart attack before?• Did you have fast
heart rates after your MI?
• If yes to both, odds of VT are 86% with a wide complex tachycardia
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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Recap of Criteria
• Start at the top of the criteria
• List all that are positive for VT
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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
Practice Cases
Ventricular Tachycardia
Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
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