EKG Flashcards
What is the inherent rate of the SA node?
60-100 BPM
What is the inherent rate of the AV node?
40-60 BPM
What is the inherent rate of the ventricles?
20-40 BPM
What does the parasympathetic nervous system vagus nerve do?
Decreases rates
Slows impulse conduction
Decreases force of contraction
What does the sympathetic nervous system do?
Increases rate
Increases force of contraction
How long is each little box?
0.04 seconds
What is the P wave?
Atria contracting
What is the QRS complex?
Ventricles contracting
What is the T wave?
Repolarization of ventricles
What is the ST interval?
The complete time for repolarization
How long should a PR interval be?
0.12-0.20 seconds
How do you measure a PR interval
From the beginning of the P wave until where the R wave begins
How long should a QRS interval be?
<0.12 seconds
How do you measure the QRS interval?
Measure from beginning of Q wave to S
How do you find the HR using EKG 6 second strip?
Count QRS complexes and multiply by 10
How many BPM in 1 big box?
300
How many BPM in 2 big boxes?
150
How many BPM in 3 big boxes?
100
How many BPM in 4 big boxes?
75
How many BPM in 5 big boxes?
60
How many BPM in 6 big boxes?
50
How many BPM in 7 big boxes?
43
What causes cardiac contraction to begin?
Depolarization of cardiac cells
What is automaticity?
The ability of cardiac cells to initiate an impulse spontaneously and continuously
What is contractility?
The muscle responding and squeezing
What is excitability?
The ability of cardiac cells to respond to an electrical impulse
What is conductivity?
Related to transmission of the impulse from one fiber to another
What metaphor can be used to remember the AV node?
AV node is a bouncer - only letting a certain amount of people into the club at a time
What does a prolonged QT interval increase the risk of?
Lethal ventricular arrhythmia
What does a QRS complex of >0.12 seconds indicate?
Bundle branch block
How long is the QT interval usually?
0.32 to 0.40 if the HR is between 65-95
