STUDY GUIDE
K
C
QUESTIONS WITH
LO
CORRECT VERIFIED
YC
ANSWERS A+ GRADED
D
U
ST
,depolarization - ANS - inside of cell becomes positive, outside negative
- contraction
- na+ channel opens
- ELECTRICAL
repolarization - ANS movement of cells = inside is negative again
- na+ channels close, k+ channels open
- MECHANICAL
p wave
K
qrs wave
t wave - ANS - (p) atrial depolarization
C
- (qrs) ventricular depolarization
- (t) ventricular repolarization
LO
refractory period - ANS per of time where cardiac cells cannot respond to stimulus
absolute refractory period - ANS beginning of qrs to peak of t wave
relative refractory (vulnerable per of repolarization) - ANS - cardiac cells have
YC
repolarized enough to respond to strong stimulus
- during this per a strong stimulus may overtake the pacemaker of the heart
- ex. PVC during vulnerable period may turn into vtach or torsades
- prolonged QT interval inc possibility
D
causes of prolonged qt intervals - ANS haldol, bradycardia, hypokalemia
U
automaticity - ANS ability of pacemaker cells to initiate electrical impulse
excitability - ANS ability of muscle cells to respond to outside stimulus
ST
conductivity - ANS ability to recieve electrical stimulus and conduct impulse to adjacent
cells
contraction - ANS cardiac cells shorten = muscular contraction in response to electrical
stimulus
sa node - ANS - primary pacemaker of heart
- 60-90 bpm
, av node - ANS delay = atrial contraction + ventricular filling
- 40-60 bpm
bundle of his - ANS ability to self initiate electrical activity
- 40-60 bpm
purkinje fibers - ANS network of fibers that carry electrical impulse to ventricular
muscle cells
- 20-40 bpm
K
NSR
Brady
C
Tachy
SVT
Junctional
LO
Ventricular rhythm - ANS NSR 60-100
Brady 40-60
Tachy >100
SVT >150
Junctional 40-60
YC
Ventricular rhythm 20 - 40
PR interval - ANS 0.12-0.20
beginning of p to beginning of qrs
D
qrs interval - ANS < 0.12
beginning of q to end of s
U
qt interval - ANS beginning of q to end of t
- heart rate dependent
ST
is rhythm regular or irregular - ANS measure interval between R waves
ventricular rate - ANS - count # of qrs complexes
atrial rate - ANS - count # of p waves
causes of bradycardia - ANS - vagal
- dig, beta blockers
- compensatory response in acute MI