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38 Cards in this Set

  • Front
  • Back
What are automaticity foci?
Focal areas of the heart that have electrical automaticity.
Where is the SA Node located?
In the upper-posterior wall of the RA.
What is the sinus node?
Another term for the SA Node.
What is the P wave on an EKG?
Depolarization and contraction of both atria.
Purpose of the AV valves?
Prevent backflow of blood and electrical insulation.
What happens to electrical conduction in the AV Node?
Depolarization slows down to allow blood flow into ventricles.
How does the AV Node conduct depolarization?
Ca++ ions.
What is the ventricular conduction system?
His Bundle and the Left and Right Bundle Branches.
What type of fibers make up the ventricular conduction system?
Purkinje fibers.
What is the QRS complex on the EKG?
It represents the depolarization of the ventricular myocardium and the initiation of contraction.
What ions are used in the depolarization of the Purkinje fibers?
Na+ ions.
Which wave is often absent on the EKG?
Q wave.
What is the ST segment?
Horizontal segment of baseline following the QRS complex.
What happens during the ST segment?
Initial phase of ventricular repolarization.
What is the T wave and what is happening?
The hump after the ST segment during which rapid ventricular repolarization occurs.
What ions are responsible for repolarization?
K+ ions.
When does systole occur on the EKG?
Begins with the QRS and persists until the end of the T wave.
Does systole span both depolarization AND repolarization of the ventricles?
What does the vertical amplitude measure on the EKG?
What is the length and width of the small boxes on the EKG graph paper?
How many mm represent 1mV on the graph?
How are positive (upward) deflections produced?
Positive charge flowing toward a positive electrode.
What is the time represented in the distance between two heavy black lines (5mm)?
0.2 seconds.
Each tiny square represents how much time?
0.04 seconds.
How many leads are there on an EKG?
12 leads = 6 limb leads + 6 chest leads.
How many electrodes represent each lead?
One pair.
What are the names of the limb leads?
Lead I, II, III and AVR, AVL, AVF.
Which are the bipolar leads?
Leads I, II, III.
Which are considered unipolar, or positive leads?
Which are the "lateral" leads?
AVL and Lead I on the left arm.
Which are the "inferior" leads?
Leads II, III, and AVF.
What are the chest leads?
6 positive electrodes positioned across the chest, centered on the AV Node.
What is the horizontal plane?
The plane formed by the positioning of the chest leads.
On what side of the heart are V1 and V2 positioned?
The right side.
On what side of the heart are V5 and V6 positioned?
The left side.
Where are V3 and V4 located relative to the heart?
Over the interventricular septum.
In what plane are the limb leads positioned?
Frontal plane.
What are trunk electrodes?
Alternative positioning of electrodes in various medical situations.