Montemayor's Stupid Fucking DSAs Flashcards
U wave
rarely seen
represents the repolarization of papillary muscles
what is a lead?
defined by two electrodes
purpose of right leg electrode?
grounding
what does the V stand for?
unipolar
augmented leads
unipolar
compare positive limb electrode with an average of the two negative electrodes
P wave
how long atrial depolarization takes
PR interval
how long for action potential to conduct through AV node before activating ventricles
QRS complex
how long it takes wave of depolarization to spread throughout ventricles
QT interval
how long ventricles remain depolarized and is thus a rough measure of overall length of ventricular action potential
sinus tachycardia
faster than normal rhythm
sinus bradycardia
slower than normal rhythm
sinus arrhythmia
subtle change in heart rate with each respiration cycle
inspiration accelerates
expiration slows
loss of sinus arrhythmia can indicate what?
loss of autonomic innervation
wolff parkinson white syndrome
abnormal conduction path
-bundle of kent
first degree AV block
slowing of conduction through the AV node
unusually long PR interval
second degree AV block
tissues conduct some impulses but not others
two types - mobitz
mobitz type I block
PR interval increases gradually with each cycle until AV node fails completely, skipping ventricular contraction
every 3rd or 4th beat fails to conduct to ventricles
mobitz type II block
PR interval constant from beat to beat
but every n’th ventricular contraction is missing (no QRS)
rate dependent block
when heart rate exceeds a certain level, the ventricular conduction fails
no time to repolarize
third degree AV block
no impulses travel either direction
complete heart block
atria and ventricle contract on their own pacemakers
AV dissociation
when the atria and ventricle contract on their own pacemakers
-when there is complete block
reentry
circus movement
can result in tachycardia (bc it acts as fast pacemaker) or fibrillation
two signs of WPW syndrome?
shortened PR interval
delta wave (positive deflection at beginning of QRS complex)
supraventricular tachycardia?
can be caused by reentry caused by WPW syndrome (alternate conduction pathway)
paroxysmal supraventricular tachycardia?
rate exceeds 150 bpm
atrial fibrillation
very fast reentry cycle