Lecture 5 Test 4 Flashcards
What is the Mean Axis?
59 degrees
Meaning of
Small arrow (Vector)?
Big Arrow?
- small electrical activity
- more electrical activity
Looking at an EKG, if the vector is coming from a negative to positive? What is the deflection?
Positive deflection
What is the deflection if the vector is up and down?
0 deflection
What is the deflection if the vector is coming from positive to negative?
Negative deflection
Where is the first part of the heart to be depolarized?
Left inner septum
Meaning of aVR
augmented voltage right side go the body; other 2 leads of the triangle would be negative (RV + Basal septum)
Meaning of aVL
Augmented voltage left side of the body; other 2 leads of the triangle would be negative (view: High lateral LV with Lead I)
Meaning of aVF
augmented voltage foot lead (inferior); other 2 leads of the triangle would be negative (View: Inferior wall with Lead II, III)
Which lead is used the least?
aVR
What does it mean if the electrical current is moving from the anterior part of the heart towards the rear (away from V2)?
Anterior heart injury (negative deflection)
What does it mean if the current is coming from the posterior part of the heart and towards V2?
Posterior heart injury (positive deflection)
Where are lateral leads located?
V5 and V6
What are anterior leads?
V1-V4
V1 would show positive or negative deflections for P, QRS, T waves?
All negative deflections because its far away from the heart
How would the deflections look on V4?
Large deflections because it’s right on top of the heart and in line with the Mean Axis
Which lead is most helpful in 12 lead?
V2 (views posterior/anterior injury)
Where are V1 and V2 placed?
Left/Right 4th intercostal space
Where does V4-V6 get placed?
Along 5th intercostal space
Where does V3 get placed?
Halfway between V2 and V4
If the depolarization and repolarization of the QRS complex goes in the same direction, your deflection would be?
Positive with a negative T wave
What is a biphasic T wave?
It’s half down and half up because its depolarizing in an abnormal way
How do you figure out the Mean arterial axis?
Add Lead I and Lead III to get Lead II
1 big box equals? (5mm x 5mm)
5mm height = 0.5 mV
5mm width = 0.2 secs
What happens if you have a resistance at the left bundle branch?
Depolarization of the right ventricle is faster
What does it mean if you have “rabbit ears” on your QRS?
There’s a bundle branch block
How do you know if it’s a left/right bundle branch?
Figure out the Mean Axis of the heart
How can you find the area of injury of the heart?
Find the area that’s stuck in a depolarized state causing an abnormal current where there shouldn’t be one.
Based on 12 lead, R wave should look?
S wave should look?
V1-V6
- small to big
- big to small
12 lead
Shows the right ventricle current
V1-V3, aVR
12 lead
Views basal septum current
V2, V3, aVR
12 lead
Views anterior wall of the heart
V2-V4
12 lead
views lateral wall
V5, V6, Lead I, aVL
small boxes in the EKG strip
1mm height = 0.1 mV
1mm width = 0.04 secs
Normal QRS size
< 0.12 secs (3 small boxes)
Normal PR interval
< 0.2 secs (5 small boxes)
