lecture 2 (chapter 5) Flashcards
describe sinus arrhythmia
normla, but extremely minimal, increase in heart rate during inspiration and an extremely minimal decrease in heart rate during expiration
atrial depolarization eventually reaches the AV node, but conduction of depolarization slows within the AV node, recording a ______ on EKG
pause
when the ventricular myocardium depolarizes, it produces a ____ on EKG
QRS complex
what is a wandering pacemaker
an irregular rhythm (normal rate range)
what a rhythm of patients with chronic obstructive pulmonary disease. The heart rate is over 100 per minute with P waves of various shapes, since 3 or more atrial foci are involved
multifocal atrial tachycardia
what does atrial fibrillation result from
multiple irritable atrial foci, suffering from entrance block, pacing rapidly
when is an automaticity focus overdrive-suppressed
if it is regularly depolarized by a pacing rate fasting than its own inherent pacing rate
what syndrome occurs when there is pacing from a ventricular focus that is so slow that blood flow to the brain is significantly reduced to the point of unconsciousness
stokes-adams syndrome
what are the most sensitive O2 sensors
ventricular automaticity foci
a premature atrial beat may be unable to depolarize the AV node if it (the AV node) is not fully depolarized and still _______ to an extra stimulus
refractory
an irritable junctional automaticity focus may fire a premature stimulus coupled to the end of each normal (SA node paced) cycle to produce ________
junctional bigeminy
an irritable junctional focus may fire a stimulus after 2 consecutive, normal sinus-generated cycles. a repeating series of these couplets is ___________
junctional trigeminy
the most likely reason for a ventricular automaticity focus to become irritable is ________
hypoxia
a solitary ventricular focus suffering from entrance block is ________
parasystolic
what is the rate range for paroxysmal tachycardia
150 to 250
what is the rate range for flutter
250 to 350
what is the rate range for fibrillation
350 to 450
what does paroxysmal mean
sudden
sudden runs of ventricular tachycardia resemble a rapid series of_____
PVCs
paroxysmal ventricular tachycardia often indicates ______
coronary insufficiency
the accessory __________ causes ventricular pre-excitation in wolfs-parkinson-white syndrome
bundle of kent
the delta wave records the ___________
depolarization of an area of ventricular pre-excitation
what is the ability of specialized cells to spontaneously generate electrical impulses which may then spread throughout surrounding tissue
automaticity
what is the rate for atrial foci
60-80 per minute
what is the rate for junctional (AV nodal) foci
40-60 per minute
what is the rate for ventricular foci
20-40 per minute
what term describes the content that the pacemaker with the fastest rate is the dominant pacemaker
overdrive suppression
describe the P wave in a sinus rhythm
positive in lead 2 and negative in lead aVR
what is the EKG criteria for a normal sinus rhythm
sinus rhythm with a heart rate between 60 and 100 beats per minute
what is the EKG criteria for sinus arrhythmia
same criteria as sinus rhythm and there is a greater than 0.16 sec difference between the shortest and the longest PP intervals within the same EKG tracing
what is the most common cause of sinus arrhythmias
respiration
what is the key to determining the origin of a completely inverted P wave in lead 2
length of the PR interval (provided that there is no AV nodal dysfunction)
describe bigeminy
every other beat is premature
describe trigeminy
every 3rd beat is premature
what is enhanced automaticity due to
irritability
describe torsades de pointes
polymorphic ventricular tachycardia (VT) which is preceded by marked prolongation of the QT interval
what is tornadoes de points facilitated by
marked QT prolongation
what is the most common mechanism of tachyarrhythmias
reentry (disorder of impulse propagation)
what does reciprocating tachycardia result from
unidirectional block followed by re-entry
what are the main criteria for wandering pacemaker
irregular rhythm: P wave shape varies, atrial rate less than 100, irregular ventricular rhythm
what is the main criteria for multifocal atrial tachycardia
irregular rhythm: P wave shape varies, atrial rate exceeds 100, irregular ventricular rhythm
