Flashcards in Basic Arrhythmias Deck (77):
What are the two types of cells in the heart?
What do electrical cells do?
Initiate and conduct impulses
What do mechanical cells do?
Contract in response to stimulation
What is polarization?
Electrical charges are balanced and ready for discharge
What is depolarization?
Discharge of energy that accompanies the transfer of electrical charges across the cell membrane
What is repolarization?
Return of electrical charges to original state
What part of the heart pathway stimulates the mechanical cells?
What is the inherent rate of the SA node?
What is the inherent rate of the AV junction?
What is the inherent rate of the ventricles?
What determines what will be the pacemaker?
The site with the fastest rate
What is the normal pacemaker?
What is it called when a site speeds up and takes over as pacemaker?
What is it called when the normal pacemaker slows down or fails and a lower site assumed pacemaker responsibility?
Sympathetic stimulation causes what three things with the heart?
Increase heart rate
Increase AV conduction
Parasympathetic stimulation causes what three things in the heart?
Decreased heart rate
Decreased AV conduction
What does the sympathetic branch influence in the heart?
Both the atria and the ventricles
What does the parasympathetic branch influence in the heart?
Is it negative or positive inside a cardiac cell?
Is it positive or negative outside a cardiac cell?
What electrolyte is inside cardiac cells?
What electrolyte is outside a cardiac cell?
What is the isoelectric line?
Straight line produced on EKG machine that means no current is flowing
If the flow of electricity is toward the positive electrode what will the EKG machine produce?
An upward deflection
If the flow of electricity is toward the negative electrode what will the EKG machine produce?
A downward deflection
How much time in between two tic marks?
What does the height of the deflection indicate?
Which lines measure voltage?
Which line measures time?
How much time is in between two heavy vertical lines on an EKG graph?
How much time is in between two lite vertical lines on an EKG graph?
(1/5th the time of bold vertical lines)
What are the five waves called in a single cardiac cycle?
What does an interval refer to?
In the area between the waves
What does a segment referred to?
A straight line or area of electrical inactivity between waves
What wave is indicative of atrial depolarization?
What is the PR segment indicative of?
The delay in the AV node
What area of the heart is the slowest conduction speed?
Why does the AV node have the slowest conduction speed?
To allow time for atrial contraction and complete filling of the ventricles
What does the PR interval monitor?
All electrical activity in the heart before the impulse reaches the ventricles
What is the first negative deflection?
The Q wave
What does the QRS complex indicate?
What is the first positive deflection following the P wave?
What is the second negative deflection following the P wave?
What wave indicates ventricular repolarization?
How long are normal PR intervals?
What does a long PRI indicate?
Delay in the AV node
How do you measure the PR interval?
Start at first deflection of p wave
End at final point of PR interval
Don't include QRS complex
How do you measure the QRS complex?
Include the beginning of Q wave
End at end of S wave
Do not include ST segment
What is the normal time range for QRS complex?
Less than .12 second
What are 4 causes for artifact on an EKG
60-cycle interference (Effect of other electrical instruments in room)
What two waves on an EKG are the refractory period?
What is the relative refractory period?
Small part of the refractory period where some of the charges are polarized and can be depolarizer if the impulse is strong enough
What is the refractory period?
Period when the heart is unable to respond to an impulse
What are the two refractory periods called?
Absolute refractory period
Relative refractory period
What is the absolute refractory period?
When absolutely no impulse can cause depolarization
When is the relative refractory period?
Downward slope of T wave
When is the absolute refractory period?
QRS interval until the apex of T wave
Where is the positive electrode placed?
Apex of heart
Where is the negative electrode placed?
Below right clavicle
Where is the ground electrode placed?
Below left clavicle
What are four of the most common major categories arrhythmias?
A normal healthy heart would be and what rhythm?
Normal sinus rhythm
What should the R wave correspond with?
What does regularly irregular mean?
There's a pattern of irregularity
What does basically regular mean?
There's a regular rhythm with a beat or two that interrupts it
What does totally irregular mean?
There's no pattern at all
How do you determine if a rhythm is regular?
R to R interval
To find the rate of a rhythm how much do you divide the total of the small squares?
To find the rate of a rhythm how much do you divide the total of the large squares?
What does supraventricular mean?
Activity occurring above the ventricles
What part of the heart conductive system is the fail safe mechanism?
The AV node
What does fail safe mechanism mean?
The AV node protects the ventricles from having to respond to too many impulses from the atria
A QRS of less than .12 second is what in origin?
What occurs if there is a conduction disturbance in the ventricles?
A wide QRS complex
What is afterload?
Resistance heart must pump against
What is preload?
The pressure on the ventricles at end of resting phase