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32 Cards in this Set
- Front
- Back
At what rate does the AV node fire?
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40-60 BPM
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At what rate does the Ventricles spontaneously fire?
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30-45 BPM
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Why won't the AV node and Ventricles fire their own beats?
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They're suppressed by the SA node
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Pathway of Electrical Conduction?
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SA Node
Intratrial Pathways AV Node Bundle of His Left and Right Bundle Branches Purkinje Fibers Endocardium Epicardium Apex--> Base |
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Who conducts the fastest?
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His and Purkinje
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What makes up a Lead?
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A pair of electrodes
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What does a little tiny square on an EKG represent?
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0.1mV
and .04 seconds |
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Which direction does the wave of depolarization of the atrium proceed in?
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Towards Apex
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What does this atrial depolarization create on the EKG?
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P wave
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Pause: what are the 4 main parts of electrophysiology represented in your normal EKG read out
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Depolarization of Atrium
Depolarization of AV Node Ventricular Depolarization Ventricular Repolarization |
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So the P wave is the Atrial Depol, what represents the AV Depolarization?
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The P-R Segment
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What part represents the Ventricular Depol?
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QRS
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What about the ole Vent. Repol?
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T wave
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Ok...wait a sec...so the T wave = repolarization, but its positive on the readout...what gives?
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Its b/c the repolarization proceeds in the opposite direction of depolarization
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What direction do depol and repol proceed in then?
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Repol goes outside (epicardium)-->in (endocardium)
Depol goes inside-->out |
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Normal Sinus Rhythm? Brady? Tach?
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Normal: 60-100
Brady: <60 Tach > 100 |
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Normal PR, QRS, and QT intervals?
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PR: 3-4 small boxes
QRS: 2-3 small boxes QT: .3-.46 sec (varies w/ HR) |
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A wave of depolarization moving TOWARD a POSITIVE electrode records a ______ deflection on the EKG?
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POSITIVE
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Which leads are in the horizontal plane?
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V1-V6
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Which lead is the ground lead?
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Right Leg
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Lead one sees?
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RA--> LA
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Lead 2 sees?
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RA--> LL
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Lead 3 sees?
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LA --> LL
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Six leads of the frontal plane?
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I
II III aVR aVL aVF |
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Which leads are the bipolar? unipolar?
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Bipolar: I, II, III
Unipolar: aVR, aVL, aVF |
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Angle of the 3 bipolar leads?
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I: 0
II: 60 III: 120 |
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Angle of 3 unipolar leads?
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aVR: -150
aVL: -30 aVF: 90 |
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Placement of Precordial Leads?
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V1: 4th ICS, R sternum
V2: 4th ICS, L Sternum V3: between V2 and V4 V4: 5th ICS MCL V5: between V4 and V6 V6: 5th ICS MAL |
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What is an R' wave?
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when there is a 2nd positive deflection after the R wave
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What is a QS wave?
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when there is a monophasic negative QRS complex
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When should you Dx a prolonged QT segment?
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when QT is more than 1/2 of R-R
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Where does the normal QRS axis point?
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Towards Apex of heart (more or less)
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