Axis Determination and Deviation

Views:
 
Category: Others/ Misc
     
 

Presentation Description

No description available.

Comments

By: smelleecat (27 month(s) ago)

wow this makes things so much easier. thanks for the presentation.

Presentation Transcript

12 Lead ECGs: Axis Determination & Deviation : 

12 Lead ECGs: Axis Determination & Deviation EMS Professions Temple College

Axis Determination & Deviation : 

Axis Determination & Deviation Why Axis Determination? Definitions Axis Quadrants Axis Determination Axis Deviation Physiologic vs Pathologic

Axis Determination & Deviation : 

Axis Determination & Deviation Why Axis Determination? “Paramedics don’t need to know this” The ability to identify hemiblocks (“fascicular blocks”) is the main reason you need to be able to determine axis “But paramedics don’t need to know this either” Should they know this?

Axis Determination & Deviation : 

Axis Determination & Deviation “It is my opinion that the inability to determine the presence of a hemiblock has often been the cause of complete heart block when well-intentioned caregivers have improperly administered lidocaine” Mike Taigman, “Taigman’s Advanced Cardiology”,Brady, 1995, p. 71

Axis Determination & Deviation : 

Axis Determination & Deviation What is Axis? “the general (mean vector) direction of electrical impulses as they travel through the heart” “the sum total of all electrical currents generated by the ventricular myocardium during depolarization” normally from upper right to lower left

Axis Determination & Deviation : 

Axis Determination & Deviation What do you need to determine the axis of an ECG? The 12 Lead ECG Leads CORRECTLY placed on the patient RA on the right arm LA on the left arm LL on the left leg Not on the chest or abdomen Knowledge of axis deviation

Axis Reference : 

Axis Reference Hexaxial Reference System The six frontal leads create six poles that intersect at the center of the heart Each pole has a positive & negative axis Each + and - end is assigned a value expressed in degrees Hexaxial then divided into quadrants (easier to use)

Axis Quadrants : 

Axis Quadrants Quadrants Left axis-30 to -90 ° Normal axis-30 to 90° Right axis90 to 180° Extreme Right axis or “No Man’s Land-90 to 180° 0° I +90° aVF +30° +60° II +120° III +150° +180° aVR -150° +120° -90° -60° aVL -30° Normal LAD RAD No Man’s Land

Axis Determination : 

Axis Determination Quick Axis Determination Determine the net QRS deflection in Leads I and aVF (positive or negative) Lead I aVF Normal axis LAD RAD ERAD

Axis Determination : 

Axis Determination Estimating Axis Quickly Determine the net QRS deflection in leads I and aVF (positive or negative) If the net QRS in Lead I is nearly the same as aVF, then axis midway between or 45° We estimate by calling it, “between +40° and +50° If the net QRS in Lead I is positive and is obviously greater than aVF, then axis closer to lead I Estimate as “Between 0° and 40°” If the net QRS in aVF is positive and greater than Lead I, then axis is +50° and +90°

Axis Deviation : 

Axis Deviation Pathologic vs Physiologic LAD First step Do I have LAD? If yes, then proceed on Look at Lead II If the net QRS deflection is more negative than positive, then the axis must be MORE NEGATIVE than -30°

Axis Determination & Deviation : 

Axis Determination & Deviation Examples for Practice