Lab 5 Flashcards
What is cardiac Axis?
general direction of electrical impulses as they travel through the heat
What is normal axis?
from upper right to lower left
What is the simple way to determine axis deviation?
using the first three leads and observing the deflection patterns
How is Normal deflection patter in Lead 1, 2, and 3?
Lead1: positive deflection pattern
Lead 2: Positive deflection
Lead 3: positive deflection
What is Right Axis Deviation (RAD)?
heart that is anatomically or electrically deviated to the right will result in an electrical vector toward the right side of the body
What will happen to the electrical vector in a right-axis deviation?
will move toward the right arm electrode resulting in a negative deflection pattern in Lead
What will happen to leads 1 and 3 during RAD?
1 is down still deflect upwards since the electrical vector still move towards the positive electrode positioned at the left leg
What is Left Axis Deviation (LAD)?
heart that is anatomically or electrically deviated to the left will result in an electrical vector toward the left side of the body
What happens in the Leads during LAD?
electrocal vector will move toward the left arm electrode resulting in a negative deflection pattern in Lead 2 and 3 /avf. Lead 1 will still deflect upwards
Heart Rate Determination: 1 tiny box=?=?
1 big box=?=?
a. 1mm=0.04 seconds
b. 5mm=0.20 seconds
How do you determine heart rate?
calculate the distance between two R waves
- using big boxes= 300/# of big boxes
- using tiny boxes= 1500/#of tiny boxes
What is PR interval?
the time interval from the beginning of the P wave until the beginning of the QRS complex through the AV Junction
What is the normal range of PR interval?
between 0.12 sec( 3tiny boxes) and 0.2 sec ( 1 big box)
What does a prolonged PR interval indicate?
> 0.2 sec = heart block
What does a abnormally short PR interval indicate?
<0.1= less blood flow to the ventricles and a lower cardiac output
