EKG Flashcards
1
Q
atrial depolarization
A
- depolarization slows
- allowing time for blood in atria to enter the ventricles
- slow conduction through AV node is carried by calcium (ca++) ions
2
Q
ventricular conduction system
A
- originates at His bundle which penetrates AV valves the immedicatley bifurcates (in the interventricular septum) int he the right and left bundle branches
- the His “bundle” and both “bundle” branches are “bundles” or rapidly conduction purkinje fibers.
- like the myocardium, purkinje fibers use fast-moving na+ ions for conduction of depolarization
3
Q
depolaizaion
A
- conducts slowly through the AV node (using ca++ ions)
- then conducts rapidly (using na+ ions) through the His bundle to the right and left bundle branches into the terminal filaments of the purkinje fibers
- which depolarizes the ventricular myocytes
4
Q
ventricular conduction system
A
- consists of rapidly conducting purkinje fibers
- terminal filaments of purkinje fibers depolarize the ventricular myocardium
- initiating ventricular contraction while inscribing a QRS complex on EKG
5
Q
entire qrs
A
represents ventricular depolarization
6
Q
st elevation or depression
A
usually a sign of serious pathology that may indicate imminent problems
7
Q
st segment
A
- represents the “plateua” (inital) phase of ventricular repolarization.
- ventricular repolarization is rather minimal during the ST segment
8
Q
t wave
A
rapid phase of ventricular repolarization
9
Q
repolarization
A
-accomplished by K+ ions leaving the myocytes
10
Q
qt interval
A
-represent the duration of ventricular systole and is measured from the beginning of the QRS until the end of the T wave
11
Q
Ca++ ions
A
produce myocardial contractions
12
Q
K+ ions
A
outflow causes repolarization
13
Q
Voltage
A
height or depth of waves measures from baseline in millimeters
14
Q
Time of small boc
A
.04 seconds
15
Q
Time of large box
A
.20 sec
=5 small boxes @ .04 sec
