EKGs Flashcards
How many electrodes are there total in a standard EKG?
10
How many limb electrodes are there in a standard EKG?
4
How many precordial electrodes are there in a standard EKG?
6
How many seconds does one small box represent on an EKG strip?
0.04 seconds
What is a voltage of Zero referred to as on an EKG strip?
Isoelectric Line
A depolarization wave starts in the SA node and then go through the atrial nodal tracts which are also known as what?
Bachmann’s Bundle
In addition to moving through fast pacemaker cells, the signal also travels through the slow myocytes in the interventricular septum; this direction is slightly away from the Lead II vector because there is a lot of tissue. This creates a negative deflection on an EKG that is known as what?
Q Wave
After tissue depolarizes, there is a brief period of time when there is no change in electrical activity; thus the EKG goes back to the isoelectric line. The exact point at which it hits that line is called what?
J Point
For a brief time after the J point, there is no net change in electrical activity. What is this known as?
ST Segment
What is the name of the final wave on an EKG strip?
T Wave
What does the T Wave represent?
Ventricular Repolarization
How many seconds does one large box represent on an EKG strip?
0.2 seconds
If there are 32 boxes between two R Waves, what is the heart rate on that EKG strip?
0.04 x 32 = 1.28 seconds between heart beats
1 / 1.28 = 0.78125 beats per second
0.7825 x 60 seconds = 46.875 bpm
46.875 bpm
How many seconds does an entire EKG strip represent?
10 seconds
If there are 15 R Waves on a 10 second EKG strip, what is the heart rate for that strip?
60 seconds/10 seconds = 6
6 x 15 R Waves = 90
90 bpm
Electrical signal coming from an ectopic focus in the atria, such as an irritated atrial cell, starts to fire between 250 - 300 depolarizations per minute.
Atrial Flutter
Electrical signal coming from multiple ectopic foci in the atria that all begin firing at once.
Atrial Fibrillation
What type of QRS complex is seen when there is a bundle branch block?
Wide QRS Complex
What is the heart rate of an individual with 1 Big Box in between the R Waves?
300 bpm
What is the heart rate of an individual with 2 Big Boxes in between the R Waves?
150 bpm
What is the heart rate of an individual with 3 Big Boxes in between the R Waves?
100 bpm
What is the heart rate of an individual with 4 Big Boxes in between the R Waves?
75 bpm
What is the heart rate of an individual with 5 Big Boxes in between the R Waves?
60 bpm
What is the heart rate of an individual with 6 Big Box in between the R Waves?
50 bpm
