🩻ECG Flashcards
Automaticity
ability of heart cells to generate action potential
Conductivity
ability for cardiac cells to transmit action potential
Rhythmicity
cardiac cells to generate an action potential in a regular rate
SA node rate
60-100 beats/min
AV node rate
40-60 beat/min
Purkinje fibers
15-40 beat/min
P wave
artial depolarization/contraction
SA firing
PR interval
time from onset art depo to vent depo
QRS interval
Art repo/vent depo
Impulse through bundle branches down purkinje
J point
point after QRS when returns to isoelectric line
ST segment
end of QRS to beginning of T wave
Elevated ST
STEMI
ST depression
NSTEMI
T wave
vent repo
influenced potassium
QT interval
time from vent depo to vent repol
Q to end of T (at isometric line) ~ 40 seconds
Systematic Approach
calculate rate, regularity, rhythm
Regularity
R to R, P to P
PR interval
0.12 - 0.2 sec 3-5 little boxes
QRS interval
<0.12 less than 3 boxes
What can prolong QT interval
amiodirone
First degree AV block
P interval longer than >0.20
Bundle Branch Black BBB)
> 0.12 prolonged QRS interval
could indicate previous MI
Artifact
different strip, reposition, pulm treatment
Normal Sinus Rhythm
Impulse 60-100
P wave present
PR interval within .12-.20
QRS is narrow <0.12s seconds
Bradycardia
HR <60
common athletes
sleep, sever pain, MI, spinal cord injury (widowmaker causes bradycardia)
Meds: digitalis, beta blockers, calcium channel blocker
Bradycardia treatment
assess BP, AxO, angina?
Meds - atropine 1.0mg IV if symptomatic q5m
if ineffective TCP, dopamine/epi
Sinus Tachycardia
> 100bpm
increase sympathetic tone (stress, exercise, stimulants)
fever, anemia, hyperthyroidism, hypoxemia, heart failure, shock
Meds: atropine, catecholamines
Treatment for tachycardia
Assess BP, axo, angina, treat cause
Meds: Beta-blocker/calcium channel blocker to decrease HR
Sinus Dysrhythmia
RR intervals irregular >0.12 seconds
increases with inspiration and gradually decreases with expiration