Exam 1 Basic EKG Flashcards
The heart has the innate ability to generate its own spontaneous action potentials without any external stimuli, a phenomenon known as __________.
Automaticity
What are the two types of cells in the heart?
Pacemaker Cells (spontaneous action potentials)
Contractile Cells
When there is a stimulation above the threshold, __________ channels cause cell-to-cell conduction resulting in depolarization.
This will release ________ to interior myocytes and causes contraction.
_______ outflow causes repolarization.
Sodium Channels
Calcium
Potassium
Once the action potential is generated by the SA node, conduction will go to the right atrium via the __________ pathway.
Conduction will also travel from the right atrium to the left atrium via ____________.
Internodal Pathway
Bachman’s Bundle
The inherent pace of the SA node.
The inherent pace of AV node.
60-100 bpm
40-60 bpm
Atrial fibrillation will result in a _______% decrease in cardiac output.
20-25% decrease in CO
The bundle of His is located in the __________.
The bundle of His has pacemaker cells that can generate an action potential at _________ beats/minute.
interventricular septum
40 to 60 bpm
The bundle branch consists of pacemakers cells that can generate _________ bpm.
20 to 40 bpm
How many mV are the large boxes?
How many mV are the small boxes?
How many seconds are the small boxes?
How many seconds are the larges boxes?
0.5 mV
0.1 mV
0.04 seconds
0.20 seconds
What does the P-wave represent?
What is the normal duration of P-waves?
Atrial Depolarization
less than 0.12 seconds
What does the PR interval represent?
What is a normal PR interval?
What is a PR interval greater than 0.20 seconds called?
PR interval represents the time from the onset of atrial depolarization (contraction) to the onset of ventricular depolarization. The pause for the blood to go from the atria to the ventricles.
0.12 to 0.20 seconds
First-degree AV block
What does the QRS complex represent?
What is the duration of the QRS complex?
Ventricular depolarization
<0.12 seconds
What does the ST segment represent?
ST segment represents the interval between depolarization and repolarization of the ventricles.
Early stages of ventricular repolarization.
Elevation > 1mm is significant (injury/ischemia)
What does the T wave represent?
Repolarization of the ventricle
What rhythms will have retrograde p-waves?
Junction rhythms
(Rhythm is coming from the AV node and back up to SA node)
Why is the latter part PR interval flat?
No contraction, so the blood can continue to flow down the ventricles.
What do we associate with a QRS complex wider than 0.12 seconds?
Bundle branch block
What causes elevated T-waves?
Hyperkalemia
When is atrial repolarization?
During QRS complex
What is the rhythm?
Sinus Rhythm
What is the rhythm?
Sinus Bradycardia
What is the rhythm?
Sinus Tachycardia
(100-150 bpm)
What is the rhythm?
Junctional Rhythm
HR 40-60 bpm
Signal starts in AV node
(look for the inverted p-wave)
What is the rhythm?
Junctional tachycardia
HR >60 bpm
Signal starts in AV node
What is the rhythm?
PSVT
(HR>150)
What does paroxysmal mean?
“comes and goes”
What is the rhythm?
Premature atrial contraction
(find the underlying rhythm and then figure out the accessory rhythm and look for compensatory pause)
What is the rhythm?
A-fib
(Think irregularly irregular)
What is the rhythm?
A-flutter
(Sawtooth pattern)
What is the rhythm?
Premature ventricular contraction; Bigeminy
What is the rhythm?
1st-degree AV Block
What is the rhythm?
Bigeminy PVC
(PVC after every other normal beat)