Date post: | 14-Dec-2014 |
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Health & Medicine |
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12 Lead Interpretation a review of the Basics
Introduction
12-Lead Interpretation is easier to read than normal ECG Interpretation
Techniques used are performed in steps
You can interpret a 12- lead ECG in 60 sec or less.
Reading a 12-Lead
There are 12 Pictures taken of the heart every time a 12-Lead is taken.
When looking at the ECG we pick out only 1 complex in every picture that represents that picture of the heart.
Leads used
Limb Leads I, II, IIl Augmented Limb Leads:
AVR, AVL, AVF, V-Leads or Precordial Leads
If you don’t label the leads, you If you don’t label the leads, you don’t know Jack!!!!!!!don’t know Jack!!!!!!!
Enthovens triangle
Triangular representation of Leads I,II,II
Augmented Voltage leads
AVR AVL AVF Uses a center ground computer
assisted
Precordial Leads
V1-V6
Additional Leads
V4R
V4R
5th intercostal space mid clavicular line
V4R
V4R
Significance of V4R in relation to RCA occulsions vs. LCA circumflex branch occulsions
Things the 12 Lead “sees”
Basics of 12 Lead ECG's: Vector
Basics of 12 Lead ECG's:Vector
Basics of 12 Lead ECG'sVector
By understanding this concept of vector and knowing the "normal" vector of each of the 12 leads of the 12 lead ECG it becomes quite easy to identify problems in the direction of depolarization. It is also from this knowledge that one identifies the Mean QRS Axis. Using the six limb leads we identify the axis in relation to what is known as the frontal plane. Two major factors help to determine this mean QRS Axis, they are:
1. The anatomical position of the heart
2. The direction of ventricular depolarization.
Basics of 12 Lead ECG's Determining AXIS
1. Leads 1 and AVF dividethe thorax into quadrants, (Left, Normal, Right, No Man's) 2. If leads 1 and AVF are both
upright then the Axis is normal. 3. If lead 1 is upright and lead
AVF is downward the Axis is Left.
Basics of 12 Lead ECG's Determining AXIS
4. If lead AVF is upright and lead 1 is downward then the Axis is Right
5. If both leads are downward then the Axis is extreme Right Shoulder and most often is Vent. Tachy
LEAD 1 LEAD 2 LEAD 3
Normal UPRIGHT UPRIGHT UPRIGHT
Physiological Left Axis
UPRIGHTUPRIGHT / BIPHASIC
NEGATIVE
Pathological Left Axis
UPRIGHT NEGATIVE NEGATIVE
Right Axis NEGATIVEUPRIGHT
BIPHASIC
NEGATIVEUPRIGHT
Extreme Right Axis
NEGATIVE NEGATIVE NEGATIVE
Evolution of an AMI
Footprints of Posterior MI
Never runs alone (always with another MI; Inferior, Lateral, and/or RVI)
Most of the Posterior Wall supplied by RCA or LCX
Look for Tall R wave in V1,V2,V3 with ST segment depression
Run Posterior Leads V7,V8,V9
““You see what you You see what you look for and only look for and only
recognize what you recognize what you KNOW”KNOW”
Example 1
Example 2
Example 3
Example 4
Example 5