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ecg chapters 4 & 5

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what are 3 reasons atrial dysrhythmias may occur?
altered automaticity, triggered activity, reentry
what kind of disorders are altered automaticity and triggered activity?
disorders in impulse formation
what kind of disorder is reentry?
disorder in impulse conduction
altered automaticity can occur in what kind of cells?
normal pacemaker cells and myocardial working cells that do not normally function as pacemaker sites. these cells depolarize and initiate before a normal impulse
when does triggered activity happen and what does it require?
during repolarization when cells are normally quiet and requires a stimulant to initiate depolarization
what is reentry?
a condition in which an impulse returns to stimulate tissue that was previously depolarized?
what does reentry require?
a potential conduction circuit or circular conduction pathway, a block within part of the circuit, delayed conduction with the remainder of the curcuit
what does reentry result in?
a single premature beat or repetitive electrical impulses resulting in short periods of rapid rhythms
an excessively rapid heart rate may compromise...
cardiac output
premature beats may be produced by the...
atria, av junction, ventricles
two premature beats in a row are called
pairs or couples
three or more premature beats in a row
run or burst
bigeminy
every other beat is a premature beat
trigeminy
every third beas is a premature beat
quadrigeminy
ectopic beat occurring every fourth complex
characteristics of the p wave in a PAC
biphasic, flattened, notched, pointed, lost in the proeceding t wave
nonconpensatory pause
if the normal beat following the premature complex occurs before it was expected
conpensatory pause
if the normal beat followin the premature conplex occurs when expected
PACs associated with a wide QRS complex are called...
aberrantly conducted PACs
what does a wide QRS complex indicate?
conduction through ventricles was abnormal
when a PAC occurs very early and close to the preceding t wave (only a p wave may be seen with no QRS after it appearing as a pause) it is called...
nonconducted or blocked PAC
what varies in a wondering pacemaker?
the differences in p wave configuration reflect gradual shifting of the dominant pacemaker b/t the SA node, the atria and the AV junction. at least 3 different p wave configurations in the same lead are required for diagnosis
what is it called when wondering atrial pacemaker is associated with a vent rate <100?
multifocal atrial tachycardia
what are 7 vagal maneuvers?
coughing, squatting, holding your breath, carotid sinus massage, cold stimulus to the face, valsalva maneuver, gagging
what are the characteristics of adenosine?
can interrupt reentry pathways that involve the AV node, rapid onset of action, short half-life, slows hr
what are supraventricular arrhythmias?
rhythms that begin above the vifurcation of the bundle of His. this includes the SA node, atrial tissue and AV juction
3 or more PACs in a row at a rate of more than 100 bpm
atrial tachycardia
atrial tachycardia that starts or ends suddenly
paroxysmal atrial tachycardia (PAT)