determing axis an hemibloq.ppt
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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
22
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”
23
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
24
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
24
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
25
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
25
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
26
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
27
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