determing axis an hemibloq.ppt

chapter

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

3

Determining Axis and Hemiblock

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Chapter 3 Objectives

• Describe the intraventricular conduction system

• Define axis and axis deviation

• Using a simple chart, determine axis and the presence of hemiblock

• Describe the clinical significance of axis deviation and hemiblock

20

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Hexaxial System

• Traditional method

• 6 limb leads at various angles

• Somewhat tedious and difficult to master

21

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

What Is Axis?

• Overall direction of travel of electrical impulses as they move through the heart

• Normal axis is downward and toward the left

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Normal Axis

• Upright complexes in Leads I, II, III

• Forces going toward all three leads

• Impulses going toward a positive, make a positive deflection

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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Physiological Left Axis

• Normal variant in adults

• Common in obesity and athletes

• Lead II can show upward or halfway deflection

• Lead III is down

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Pathological Left Axis

• Disease process

• Suggests anterior hemiblock

• Patients are 4 times more likely to arrest with a hemiblock and “chest pain”

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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Right Axis Deviation

• Rare occurrence in adults

• Almost always pathological

• Associated with posterior hemiblock

• Lead I down and Lead III up

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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Extreme Right Axis Deviation

• Indeterminate axis

• Usually ventricular in origin

• Down in all three leads, I, II, III

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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Fascicular Block (Hemiblock)

• A block of one of the two fascicles of the left bundle

• ECG diagnosis

• Based on axis deviation

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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Anterior Hemiblock

• Pathological left axis• 4x higher mortality

rate when with an AMI

• Proximal occlusion until proven otherwise

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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Posterior Hemiblock

• Right axis deviation

• Very high mortality with an AMI

• Serious problem involving two coronary arteries

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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

To Determine Axis

• Run Leads I, II, and III

• Leads must be on the limbs!

• Look at the net QRS deflection in each lead (does it go up or down, or halfway)

• Compare to the rapid axis and hemiblock chart

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Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Calculated Axis Angle

• Machine calculates this for you

• Use it with your chart

• Look at the “QRS axis” or the “R axis” on some units

• Follow the chart

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Rapid Axis and Hemiblock Chart27

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Practice 12-Leads

Use the Rapid Axis and Hemiblock Chart!

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Pathological Left

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Normal Axis

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Physiological Left

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Normal Axis

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Physiological Left

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Physiological Left

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Pathological Left

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Pathological Left

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Pathological Left

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Pathological Left

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Right Axis Deviation

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Anterior Hemiblock

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Normal Axis

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Physiological Left

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Normal Axis

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Physiological Left

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Physiological Left

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Anterior Hemiblock

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Anterior Hemiblock

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Anterior Hemiblock

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Anterior Hemiblock

Page, 12-Lead ECG for Acute and Critical Care Providers© 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Posterior Hemiblock