Chapter 7 (Exam 2) Flashcards
____ Refers to the direction of the movement of depolarization, which stimulate the ____ to contract
Axis // Myocardium
The progressive depolarization of the ____ moves in a certain direction
Myocardium
Axis refers to the ____ of depolarization as it passes through the heart
Direction
General direction of the movement of depolarization can be demonstrated using a ____
Vector (arrow)
The vector shows the direction in which ___ is moving
Depolarization
The QRS complex represents the simultaneous depolarization of both ___
Ventricles
The mean QRS vector is the sum of all the smaller vectors of ____ depolarization
Ventricular
The AV node is considered to be the origin of the QRS vector, so the “tail” of the vector is always the __
AV Node
The mean QRS vector normally travels ___ and to the ____
Downward // left
We can use a ___ axis to determine the position of the mean QRS vector
Circular
The center of the circular axis is located in the ___
AV node
A normal Vector points downward and to the left, which is between __ and __ on the axis
0 degrees // +90 degrees
The axis of the heart is seen from the __ plan
Frontal
If the heart is rotated towards the right, the vector goes towards ___ (occurs in tall people)
Right
In obese people the diaphragm and heart are pushed up, and therefore the vector moves directly to the __
Left
In a hypertrophied heart, the vector is pulled towards __
The hypertrophy side
There is increased depolarization in a ___ ventricle
Hypertrophied
Vector is pulled towards the ___ that is hypertrophied
Ventricle
In a MI (myocardial infarction) there is a necrotic (dead) area. How does this affect the blood supply there?
No blood supply in the dead area
In a MI there is no blood supply in the affected area. How does this affect the vector
Vector is pulled away from the dead area and towards opposing side
Lead 1: ___ ___ is positive, ___ ___ is negative
Left arm // right arm
Lead II, III, and AVL are the ___ leads
Inferior
Lead I and AVF are the ___ leads
Lateral
When determining rotation of the heart (axis) which limb leads do you focus on only?
Lead I & AVF
___ is the only horizontal lead. ___ is the only vertical lead
Lead I // AVF
A positive lead I points the vector towards the ___ side of the circle. A negative lead one points towards the ___ side of the circle
Left // Right
A positive AVF points the vector towards the ___ side of the circle. A negative AVF points the vector towards the ___ side of the circle
Bottom // Top
Bottom left quadrant of circle represents ___
Normal range
Upward left quadrant of circle represents __
LAD (left axis deviation)
Bottom right quadrant represents ___
RAD (right axis deviation)
Top right quadrant represents
ERAD (extreme right axis deviation)
When positive and negative deflections are about the same amplitude or close to, it is called __
Isoelectric
To determine your axis, look at the deflections of leads ___ and ___
Lead 1 // AVF
Your most isoelectric limb lead will tell you what?
Where on the axis you will start before rotating
Once you have found where on the axis you will start (using the most isoelectric lead) you will rotate ___ degrees towards ___
90 // towards the axis you determined you should end in (using lead I and AVF)
When using a 12 lead EKG, which leads do you NOT look at to determine rotation of the heart?
Chest leads (V1 - V6)
If we HAD to use chest leads to determine rotation of heart, we would see that V3 and V4 are usually __
Isoelectric
IF we had to use chest leads to determine rotation of heart, If V1 or V2 are the most isoelectric that would mean there is ___ rotation
Rightward
IF we had to use chest leads to determine rotation of the heart, if V5 and V6 are mostly isoelectric that would mean there is __ rotation
Leftward
