The Only EKG Book You'll Ever Need (Chapter 1) Flashcards
at rest, cardiac cells are electrically ____
negative
fundamental electrical event of the heart
depolarization
after depolarization, cardiac cells restore to their resting polarity through
repolarization
SA node (sinus node) rate
60-100 times/min
3 characteristics of wave
- duration
- amplitude
- configuration
bundle of His emerges into
right and left bundle branches
carries current down right side of interventricular septum all the way to the apex of right ventricle
right bundle branch
left bundle branch divides into
3 major fascicles:
- septal fascicle
- anterior fascicle
- posterior fascicle
carries current down posterior surface of left ventricle
posterior fascicle
carries current down anterior surface of left ventricle
anterior fascicle
carries current down interventricular septum
septal fascicle
first downward deflection
Q wave
first upward deflection
R wave
second upward deflection
R’ (R-prime)
measures time from start of atrial depolarization to start of ventricular depolarization
PR interval
measures time from end of depolarization to start ventricular depolarization
PR segment
records time from end of ventricular depolarization to start of ventricular depolarization
ST segment
measures time from start of ventricular depolarization to end of ventricular repolarization
QT interval
measures time of ventricular depolarization
QRS interval
limb leads
I, II, III, avL, avR, avF
lead I angle of orientation
0 degrees
lead II angle of orientation
+ 60 degrees
lead III angle of orientation
+ 120 degrees
lead I is created by making ____
left arm positive and right arm negative
lead II is created by making ____
legs positive and right arm negative
lead III is created by making ____
legs positive and left arm negative
lead avL angle of orientation
- 30 degrees
lead avR angle of orientation
- 150 degrees
lead avF angle of orientation
+ 90 degrees
lead avL created by making ____
left arm positive and other limbs negative
lead avR created by making ____
right arm positive and other limbs negative
lead avF created by making ____
legs positive and other limbs negative
inferior leads
leads II, III, avF
left lateral leads
leads I, avL, V5, and V6
V1 is placed in the ____
4th intercostal space to the RIGHT of the sternum
V2 is placed in the ____
4th intercostal space to the LEFT of the sternum
V3 is placed ____
between V2 and V4
V4 is placed in the ____
5th intercostal space in the midclavicular line
V5 is placed ____
between V4 and V6
V6 is placed in the ____
5th intercostal space in the midaxillary line
anterior leads
V1, V2, V3, and V4
