1. 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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ Rapid Axis and Hemiblock Chart 27

16. 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!

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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