WITH ANSWERS
causes of prolonged qt intervals - CORRECT ANSWERS-haldol, bradycardia, hypokalemia
automaticity - CORRECT ANSWERS-ability of pacemaker cells to initiate electrical impulse
excitability - CORRECT ANSWERS-ability of muscle cells to respond to outside stimulus
conductivity - CORRECT ANSWERS-ability to recieve electrical stimulus and conduct impulse
to adjacent cells
contraction - CORRECT ANSWERS-cardiac cells shorten = muscular contraction in response to
electrical stimulus
sa node - CORRECT ANSWERS-- primary pacemaker of heart
- 60-90 bpm
av node - CORRECT ANSWERS-delay = atrial contraction + ventricular filling
- 40-60 bpm
bundle of his - CORRECT ANSWERS-ability to self initiate electrical activity
- 40-60 bpm
purkinje fibers - CORRECT ANSWERS-network of fibers that carry electrical impulse to
ventricular muscle cells
- 20-40 bpm
,NSR
Brady
Tachy
SVT
Junctional
Ventricular rhythm - CORRECT ANSWERS-NSR 60-100
Brady 40-60
Tachy >100
SVT >150
Junctional 40-60
Ventricular rhythm 20 - 40
depolarization - CORRECT ANSWERS-- inside of cell becomes positive, outside negative
- contraction
- na+ channel opens
- ELECTRICAL
repolarization - CORRECT ANSWERS-movement of cells = inside is negative again
- na+ channels close, k+ channels open
- MECHANICAL
p wave
qrs wave
t wave - CORRECT ANSWERS-- (p) atrial depolarization
- (qrs) ventricular depolarization
- (t) ventricular repolarization
refractory period - CORRECT ANSWERS-per of time where cardiac cells cannot respond to
stimulus
, absolute refractory period - CORRECT ANSWERS-beginning of qrs to peak of t wave
relative refractory (vulnerable per of repolarization) - CORRECT ANSWERS-- cardiac cells have
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
PR interval - CORRECT ANSWERS-0.12-0.20
beginning of p to beginning of qrs
qrs interval - CORRECT ANSWERS-< 0.12
beginning of q to end of s
qt interval - CORRECT ANSWERS-beginning of q to end of t
- heart rate dependent
is rhythm regular or irregular - CORRECT ANSWERS-measure interval between R waves
ventricular rate - CORRECT ANSWERS-- count # of qrs complexes
atrial rate - CORRECT ANSWERS-- count # of p waves
causes of bradycardia - CORRECT ANSWERS-- vagal
- dig, beta blockers
- compensatory response in acute MI
- ischemic heart disease
- sick sinus. synd