The axis presentation

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Learn how & why to determine the QRS axis

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  • IntroductionDon’t be alarmed by the title of this presentation
  • “How is that going to change your treatment?”, usually verbalized by someone who doesn’t understand the advanced information that you have available. It is the wrong question… think about it… how does your treatment change after any EMS class or continuing education course? It usually doesn’t change at all…what changes is your ASSESSMENT. How does knowing how to interpret ECGs change your treatment at all?Axis determination is very similar to the ability to differentiate lung sounds.
  • Many complicated phrases
  • We all have our own way of getting things done…
  • Here is a 45 year old male complaining of chest pain, what’s wrong with his ECG?
  • ERAD Never normal
  • Hopefully that list of pathologies provides a little motivation
  • 4 chambersLeft ventricle is the largestImpulse usually originates in SA NodeTravels down intranodal pathwaysTo AV NodeThe AV node pauses the impulse to allow for the vetricles to fill. AV junctionBundle Branches
  • When we are talking about the electrical axis of the heart, we are most concerned with the ventricular axis: What part of the EKG is representative of Ventricular conduction? this is represented by the QRS complex..
  • Like ripples from a stone in a pond.
  • So lets explain what this means…
  • Einthoven’s arms and his left leg are immersed in buckets of salt water. At the time, this was the only way to obtain a signal for the electrocardiograph. Even after the invention of the electrode, they continued to be placed on the subject’s arms and legs. From this configuration, leads I, II, and III were born, and they are called the limb leads to this day.
  • I know what you’re thinking. This equation is scary. If I just lost you. Take a deep breath! Everything is going to be okay. What is lead I? It is a dipole, with the negative electrode at the right arm (white electrode) and the positive electrode at the left arm (black electrode).What is lead III? It is a dipole with the negative electrode at the left arm (black electrode) and the positive electrode at the left leg (red electrode). Sometimes I wonder why Einthoven didn’t call this lead II.
  • As you can see, when you plug in the measurements, you end up with an electrical value of zero.You can try this trick on virtually any ECG.Because this is true, leads I, II, and III can be represented as an electrically equilateral triangle.
  • is the interventricular septum, which depolarizes in a left-to-right direction (responsible for the so-called septal Q waves in the lateral leads of a normal 12 lead ECG).depolarizes from a endocardial-to-epicardial direction (inside-out). Finally, the lateral walls of the left and right ventricle depolarize and last the high lateral wall of the left ventricle. This is just to give you a general idea. Obviously we can’t look at the anterior and posterior walls from a cross section of the frontal plane.
  • The mean electrical vector = the general direction of depolarizationThis is he axis we are trying to detrmine
  • Breakout exercise
  • .In physics, two vectors (or in this case leads) are equal as long as they are parallel and of the same intensity and polarity. Therefore, we can move the leads [...] to a point passing through the center of the heart, and they will be the same
  • Because this is true we can intersect the leads
  • We can do the same thing with the augmented leads
  • The most equiphasic lead is aVR (Don’t let the st-elevation confuse you)- The lead perpendicular to aVR is lead III- Lead III is mostly negative- The hexaxial diagram shows negative lead III at -60 degrees. -60 degrees indicates Left Axis Deviation (LAD)
  • Left Anterior Fascicular Block CausesChronic hypertensionAortic stenosisAortic root dilationDilated cardiomyopathyImpairment of the cardiac electrical conduction systemAcute myocardial infarctionLung diseasesAgingDegenerative fibrotic disease
  • ERAD Never normal
  • Counterclockwise rotation, indeterminate axis
  • ERAD Never normal
  • A LBBB doesn’t always cause late r-wave progression, but it is common.
  • T-wave concordance is abnormal with BBB. A RBBB will always cause early r-wave progression
  • 2:1 a-flutter, AWMI
  • V-tach
  • RBBB & LAFB, Bifascicular block
  • L axis deviation, WPW & LVH w/strainP-pulmonale & LAE
  • LBBB
  • PACED, ERAD & Precordial concordance
  • ERAD Never normal
  • Here is a 45 year old male complaining of chest pain, what’s wrong with his ECG?
  • The axis presentation

    1. 1. The ECG Axis Adam Thompson, EMT-P
    2. 2. WARNINGAxis determination is not as difficult tounderstand as people think. It is thefoundation of ECG interpretation. Don’t tryto understand everything, choose themethod that suits you best!
    3. 3. Cardiology StuffPlease askquestions!!Don’t worry, I’llexplain this stuff
    4. 4. The 6-Step Method• 1. Rate & Rhythm• 2. Axis Determination• 3. Intervals• 4. Morphology• 5. STE-Mimics• 6. Ischemia, Injury, & Infarct
    5. 5. Axis Determination Thompson 107ECG – 32 45 y/o Male with Chest PainECG – 32This is an example of Reversed Limb Leads.When lead I is negative and aVR is positive, there should be a concern about limb leadreversal. aVR will almost never be this positively deflected with a supraventricular
    6. 6. Pathologies Frontal Plane Axis Precordial Axis ERAD Right Axis Pathological Early Transition Late Transition Deviation Left Axis Counterclockwise Clockwise -90 to 180 90 to 180 Deviation Rotation Rotation -30 to -90• Ventricular • May be normal • Pregnancy • Posterior wall • SometimesRhythm • LPFB • LAFB infarction Normal,• Paced • Pulmonary • WPW • RVH especially inRhythm disease • RBBB women • Pulmonary• Dextrocardia • RVH disease • WPW • Anterior MI• Electrolyte • RBBB • LBBB • LVHderangement • WPW • Hyperkalemia • LAFB • Dextrocardia • Q-waves, MI • LBBB •Venrticular • Lung Disease Rhythm
    7. 7. Ventricular Axis
    8. 8. Ventricular Depolarization
    9. 9. What’s Normal?• The normal QRS Axis is about 60°• This can vary, and the normal range is between 0° to 90° - aVF II- -90° -60° III- -120° aVR+ -30° aVL+ -150° 0° I- +/-180° I+ 30° aVL- 150° aVR- 120° 60° III+ 90° II+ aVF+
    10. 10. Willem Einthoven Won the Nobel Prize in Physiology or Medicine in 1924 for inventing thestring galvanometer which was the first EKG.
    11. 11. Einthoven’s Triangle• Electrically, leads I, II, & III form an equilateral triangle.• Einthoven’s Law I + (-II) + III = 0
    12. 12. Einthoven’s Law• How it works• Lead I – The R wave is about 7 1/2 mm tall. – The S wave is about 2 1/2 mm deep. – Subtract the S wave from the R wave • you come up with 5 mm.
    13. 13. Einthoven’s Law• Lead I = 5mm• Lead II – It’s essentially a monophasic QS complex. – About -10 mm.
    14. 14. Einthoven’s Law• Lead I = 5mm• Lead II = -10mm• Lead III – R wave that is about 1 mm high. – The S wave is about 16 mm deep. – Subtract the S wave from the R wave. – -15 mm.
    15. 15. Einthoven’s Law• Lead I = 5mm• Lead II = -10mm• Lead III = -15mm – Plug the numbers in. I + (-II) + III = 0 5 + 10 -15 = 0
    16. 16. Einthoven’s LawThe equilateral triangle
    17. 17. Electrical AxisVentricular depolarization
    18. 18. Mean Vector
    19. 19. Mean Vector
    20. 20. The Hexaxial Reference System I III II
    21. 21. Hexaxial Diagram
    22. 22. Hexaxial Diagram aVF- II- -90° - III- 60° aVR aVL - aVR+ 120° -30° aVL+ -150° I 0° I- +/-180° I+ 30° aVL- 150° aVR- 120° 90° 60°III II aVF III+ II+ aVF+
    23. 23. The Hexaxial Reference System aVF - II- -90° III- -60° -120°aVR+ aVL+ -30° -150° 0°I- I+ +/-180° 30°aVL- 150° aVR- 60° 120° III+ 90° II+ aVF+
    24. 24. The Hexaxial Method Axis Determination Thompson 66We –only need to concentrate on the first six leadsECG 13 ECG – 14
    25. 25. Hexaxial MethodThe Hexaxial Method 5 Easy StepsStep 1: Determine the equiphasic lead.Step 2: Find that lead on the diagram.Step 3: Find the perpendicular lead.Step 4: Determine if it is positive or negative.Step 5: Find your Axis. The Hexaxial Method will determine the mean Q
    26. 26. The Hexaxial Method Axis Determination Thompson 66Step131: Find the equiphasic lead aVF- ECG – II- -90° III- -60° -120° aVR+ -30° aVL+ -150° I- 0° I+ +/-180° 30° aVL- 150° aVR- 60° 120° 90° ECG – 14Step 4: Is the perpendicular lead III+ II+ aVF+ positive or negative?
    27. 27. on T QRS Axis Hexaxial Method -90 5 Easy StepsStep 1: Determine the equiphasic lead. ERAD LADStep 2: Find that lead on the diagram. 180 0Step 3: Find the perpendicular lead. RAD NormalStep 4: Determine if it is positive or negative.Step 5: Find your Axis. 90 The Hexaxial Method will determine the mean QRS axis in the frontal plane.
    28. 28. Hexaxial MethodThe Hexaxial Method 5 Easy StepsStep 1: Determine the equiphasic lead.Step 2: Find that lead on the diagram.Step 3: Find the perpendicular lead.Step 4: Determine if it is positive or negative.Step 5: Find your Axis. The Hexaxial Method will determine the mean Q
    29. 29. The Hexaxial MethodAxis Determination Thompson 36Answer: Let’s try another oneECG – 2- The most equiphasic lead is aVR (Don’t let the st-elevation confuse you)- The lead perpendicular to aVR is lead III- Lead III is mostly negative
    30. 30. The Quadrant Method -90 ERAD LAD180 0 RAD Normal 90
    31. 31. Quadrant Method aVF - aVF - Negative QRS Negative Positive Complex in aVF-I QRS in QRS in I+ -I I+ Lead I Lead I Positive QRS Complex in aVF aVF + aVF +
    32. 32. Quadrant methodAxis Determination Thompson 66ECG – 13ECG – 14Is Lead I up or down?
    33. 33. Quadrant Method aVF - -I I+ aVF +
    34. 34. Quadrant methodAxis Determination Thompson 66ECG – 13ECG – 14Is aVF up or down?
    35. 35. Quadrant Method aVF - -I I+ aVF +
    36. 36. Quadrant Method aVF - -90 ERAD LAD-I I + 180 0 RAD Normal aVF + 90
    37. 37. Practice Quadrant MethodECG – 5 ECG – 5 is an example of Left Axis Deviation (LAD). - Since Lead I is mostly positive, we shade out the negative (left) side of the diagram. - Since aVF is mostly negative, we shade the positive (top) side of the diagram. - The NorthEast corner is remaining, indicating LAD.
    38. 38. Hexaxial Method Frontal Plane Axis Pathologiesepshasic lead.diagram.ar lead.itive or negative.
    39. 39. Print Master
    40. 40. Fascicular Block
    41. 41. If all else fails…
    42. 42. Precordial Axis Limb Leads Precordial LeadsLead I aVR V1 V4Lead II aVL V2 V5Lead III aVF V3 V6
    43. 43. Pathologies Frontal Plane Axis Precordial Axis ERAD Right Axis Pathological Early Transition Late Transition Deviation Left Axis Counterclockwise Clockwise -90 to 180 90 to 180 Deviation Rotation Rotation -30 to -90• Ventricular • May be normal • Pregnancy • Posterior wall • SometimesRhythm • LPFB • LAFB infarction Normal,• Paced • Pulmonary • WPW • RVH especially inRhythm disease • RBBB women • Pulmonary• Dextrocardia • RVH disease • WPW • Anterior MI• Electrolyte • RBBB • LBBB • LVHderangement • WPW • Hyperkalemia • LAFB • Dextrocardia • Q-waves, MI • LBBB •Venrticular • Lung Disease Rhythm
    44. 44. The Precordial Axis V1 V2 V3 V4 V5 V6
    45. 45. Precordial AxisNormal R-wave progression Axis Determination Thompson 93 ECG - 20 ECG – 20 This is a rare example of an isolated Lateral Wall Infarct. This injury pattern is nearly always due to an occlusion to the Left Circumflex (LCx). 5 Easy Steps
    46. 46. Precordial Axis Axis Determination Thompson 100Early26R-wave progression ECG – ECG – 26 This ECG is an example of Right Bundle Branch Block (RBBB). RBBB is present when a wide supraventricular rhythm presents with a positive terminal deflection in V1. Other findings include appropriate T-wave discordance, and a slurred S-wave in Lead I
    47. 47. Precordial Axis Axis Determination Thompson 90Late– 17 ECG R-wave progression ECG – 17 This is an example of an Antero-Septal MI, with some lateral wall extension. This is likely due to a proximal occlusion of the Left Anterior Descending coronary artery (LAD). The LAD, termed ―Widow Maker‖, supplies predominately the left ventricle.
    48. 48. Bundle Branch Blocks
    49. 49. Bundle Branch BlocksLeft Bundle Branch Block 1 2 3
    50. 50. Bundle Branch BlocksRight Bundle Branch Block 1 2 3
    51. 51. Bundle Branch Blocks V1 V1
    52. 52. Bundle Branch BlocksV1 = RBBBV1 GT = LBBB
    53. 53. BBBs
    54. 54. BBBs
    55. 55. RBBB Morphologies
    56. 56. LBBB Morphologies
    57. 57. Pathologies Frontal Plane Axis Precordial Axis ERAD Right Axis Pathological Early Transition Late Transition Deviation Left Axis Counterclockwise Clockwise -90 to 180 90 to 180 Deviation Rotation Rotation -30 to -90• Ventricular • May be normal • Pregnancy • Posterior wall • SometimesRhythm • LPFB • LAFB infarction Normal,• Paced • Pulmonary • WPW • RVH especially inRhythm disease • RBBB women • Pulmonary• Dextrocardia • RVH disease • WPW • Anterior MI• Electrolyte • RBBB • LBBB • LVHderangement • WPW • Hyperkalemia • LAFB • Dextrocardia • Q-waves, MI • LBBB •Venrticular • Lung Disease Rhythm
    58. 58. Bundle Branch Blocks
    59. 59. Bundle Branch Blocks
    60. 60. Practice
    61. 61. Practice
    62. 62. Practice
    63. 63. Pathologies Frontal Plane Axis Precordial Axis ERAD Right Axis Pathological Early Transition Late Transition Deviation Left Axis Counterclockwise Clockwise -90 to 180 90 to 180 Deviation Rotation Rotation -30 to -90• Ventricular • May be normal • Pregnancy • Posterior wall • SometimesRhythm • LPFB • LAFB infarction Normal,• Paced • Pulmonary • WPW • RVH especially inRhythm disease • RBBB women • Pulmonary• Dextrocardia • RVH disease • WPW • Anterior MI• Electrolyte • RBBB • LBBB • LVHderangement • WPW • Hyperkalemia • LAFB • Dextrocardia • Q-waves, MI • LBBB •Venrticular • Lung Disease Rhythm
    64. 64. Axis Determination Thompson 107ECG – 32 45 y/o Male with Chest PainECG – 32This is an example of Reversed Limb Leads.When lead I is negative and aVR is positive, there should be a concern about limb leadreversal. aVR will almost never be this positively deflected with a supraventricular
    65. 65. The End
    66. 66. Questions?
    67. 67. Other Lectures• Basic Arrhythmias• STEMI vs. STE-Mimics• CHF & Cardiogenic Shock• ACLS Explained• Airway, Airway, Airway• Acid-Base is EVERYTHING• Septic Shock… Yea, it’s that important• Neurologic Emergencies• Young Death• Spinal Trauma

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