EKG Chap 2 Flashcards
What is the smallest division on EKG ruled graph paper?
1 mm long & 1 mm high
Between the heavy black lines, how many small squares are there?
5
The height or depth of waves is measured from where?
from the baseline; in mm
What is the height or depth of waves a measurement of?
voltage
An upward deflection represents what?
amplitude
Vertical amplitude represents a measure of what?
voltage
Positive deflections appear how on an EKG?
upward
Negative deflections appear how on an EKG?
downward
The amount of time represented by the distance between 2 heavy black lines is?
0.2 seconds
Each small division (measured horizontally between 2 fine lines) represents?
.04 seonds
By measuring along the horizontal axis, what can be determined?
the duration of any part of a cardiac cycle
The amount of EKG graph paper that passes out of the EKG machine in .12 second is how many small squares?
3
A standard EKG is composed of?
6 limb leads & 6 chest leads
Electrodes placed on the right & left arms, and the left legs are what?
limb leads
How may electrodes are used to record a lead?
2
A pair of electrodes for each lead are called?
bipolar leads
Why are bipolar leads called such?
one is positive and one is negative
By selecting a different pair of electrodes for each lead, 3 separate bipolar limbs can be created and are called?
lead I, lead II, lead III
What is the bipolar limb lead configuration sometimes called?
Einthoven’s triangle
By pushing the 3 bipolar limb leads to the center of the triangle, what do you get?
three intersecting lines of reference
The AVF lead uses the left foot electrode as?
positive
In AVF, both the right and left arm electrodes are channeled into a common ground that has what kind of charge?
negative
For the AVR lead, the right arm electrode is what charge?
positive
For the AVR lead, the right arm electrode is positive and the remaining two electrodes are what charge?
negative
To obtain the AVL lead, the Left arm electrode is made what charge?
positive
What are the other two electrodes , if for the AVL lead, the left arm electrode is made positive?
negative
AVR equals what?
Right arm positive
AVL equals what?
Left arm positive
AVF equals what?
Foot (left foot) positive
What are AVR, AVL, and AVF?
augmented (or unipolar) limb leads
At what angle do AVR, AVL, and AVF leads intersect?
60 degree angles
Do the angles for AVR, AVL and AVF differ from the bipolar limb leads I, II, III?
yes
What do the 6 limb leads consist of?
three bipolar leads I, II, III and three augmented leads AVR, AVF, and AVL
what is the flat plane of the limb leads called?
the frontal plane
Does the EKG record the same cardiac activity in each lead?
yes
What do the waves look different in various leads?
Because the heart’s electrical activity is recorded from a different angle for each lead
What is the advantage of observing the EKG from six different angles?
It gives a much greater and more accurate perspective
What are leads I and AVL called?
lateral leads
Why are leads I and AVl called lateral leads?
because each has a positive electrode positioned laterally on the left arm
What are leads II, III, and AVF called?
inferior leads
Why are leads II, III, and AVF called inferior leads?
because each of these leads has a positive electrode positioned inferiorly on the left front
Name the six chest leads
V1, V2, V3, V4, V5, V6
How are the 6 chest leads positioned?
In successive steps from the patient’s right to the left side of the chest
The positioning of the 6 chest leads does what?
cover the heart in its normal anatomical position within the chest
What is the plane of the chest leads called?
horizontal plane
What does the horizontal plane of the chest leads do?
it cuts the body into top and bottom halves
If lead V1 through V6 are imagined to be the spokes of a wheel, where is center of the wheel located?
AV Node
What does lead V2 describe?
a straight line directly from the front to the back of the patient
In lead V2, the patient’s back is considered to be what?
negative
In V1, the QRS complex is normally what?
negative
In V6, the QRS complex is mainly what?
positive
Is the mainly positive QRS complex moving towards or away from the positive chest electrode of V6?
toward
What are leads V1 and V2 called?
the “right” chest leads
Why are V1 and V2 called the “right” chest leads?
because they are oriented over the right side of the heart
What are leads V5 and V6 called?
left chest leads
Why are leads V5 and V6 called “left” chest leads?
Because they are oriented over the left side of the heart
Where are leads V3 and V4 oriented over?
the area of the interventricular septum
What courses through the interventricular septum?
The Right and Left Bundle Branches
An EKG recorded from trunk electrodes can record the same information as what?
Ankly or wrist electrode for a given limb lead
Where are the electrode locations for trunk electrodes?
shoulders and abdomen
