Dubin first2 Flashcards
parasystolic
when an automaticity foci has an entrance block, and paces but cannot be overdrive suppressed
irregular rhythms
usually caused by multiple active automaticity sites
entrance block
blocks incoming depolarization in automaticity foci, cannot be overdrive suppresed
wandering pacemaker
an irregular rhythm produced by the pacemaker activity wandering from the SA Node to nearby atrial automaticity foci
wandering pacemaker
p’ wave shape varies, atrial rate less than 100, irregular ventricular rhythm
P’ wave
atrial depolarization by an automaticity focus, as opposed to normal sinus-paced p waves
multifocal atrial tachycardia (MAT)
irregular rhythm, p’ wave shape varies, atrial rate exceeds 100, irregular ventricular rhythm
multifocal atrial tachycardia (MAT)
a rhythm of patients with Chronic Obstructive Pulmonary Disease (COPD), with P’ waves of different shapes, since three or more atrial foci are involved
atrial fibrillation
irregular rhythm, continuous chaotic atrial spikes, irregular ventricular rhythm
atrial fibrillation
caused by the continuous rapid-firing of multiple atrial automaticity foci. no single impulse depolarizes the atria completely and only occasional ones reach AV node to be conducted to ventricles, no p waves
sinus arrhythmia
considered normal, varies with respiration, constant p waves
escape rhythm
an automaticity focus escapes overdrive suppression to pace at its inherent rate
escape beat
an automaticity focus transiently escapes overdrive suppression to emit one beat, due to sinus block
sinus arrest
when a sa node ceases pacemaking completely
junctional automaticity focus
pacing from av node, conducts to ventricles, may depolarize atria from below producing inverted p’ waves with an upright qrs
junctional automaticity focus
retrograde (inverted) p’ wave immediately before each qrs, after each qrs, or within each qrs
stoke’s adams syndrome
pacing from ventricular focus so slow that blood flow to the brain is reduced to the point of unconsciousness
ventricular escape beat
produces enormous QRS complex, caused by burst of parasympathetic activity that depresses SA node and atrial and junctional foci
premature beat
originates in an irritable automaticity focus that fires spontaneously, producing a beat earlier than expected in the rhythm
atrial, junctional
____ and ____ foci become irritable bc of adrenaline, increased sympathetic stimulation, caffeine, digitalis, hyperthyroidism, (adrenergic substances) stretch, low O2
premature atrial beat (PAB)
originates suddenly in an irritable focus, produces a P’ wave earlier than expected, or hides in T wave, making it taller than usual
resets
a center of automaticity ____ its rhythm when it is depolarized by a premature stimulus
aberrant ventricular conduction
if ventricular conduction system is depolarized by a Premature Atrial Beat but one Bundle Branch is not completely repolarized (still a little refractory), produces slightly widened QRS for one cycle
non-conducted
a ________ premature atrial beat is unable to depolarize a refractory AV node, no ventricular (QRS) response, does depolarize SA node to reset the pacemaking cycle
atrial bigeminy
an irritable automaticity focus fires a Premature Atrial Beat that couples to the end of a normal cycle, and repeats this process by coupling a PAB to the end of each successive normal cycle, resets cycle
couplet
the cycle containing the premature beat together with the cycle or cycles to which it couples
atrial trigeminy
when an irritable atrial focus prematurely fires after 2 normal cycles repeatedly
premature junctional beat
when an irritable focus in the av junction spontaneously fires a stimulus, widened qrs
junctional bigeminy
when an irritable junctional focus fires a premature stimulus coupled to the end of each normal cycle
junctional trigeminy
when an irritable junctional focus fires a stimulus after two consecutive normal cycles
ventricular
a _____ focus can be made irritable by low O2, Low K+, pathology (mitral valve prolapse)
Premature Ventricular Complex (PVC)
produced on EKG by irritable ventricular focus that suddenly fires, occur early in cycle, easily recognized by their great width and enormous amplitude, usually opposite polarity of normal QRS, weaker pulse bc ventricles aren’t filled yet
unifocal
6 or more PVCs per minute is pathological, if they are identical, they are _____ (from the same focus)
ventricular bigeminy
when a PVC becomes coupled with a normal cycle with every cycle
ventricular trigeminy
when a PVC couples with every two normal cycles
ventricular parasystole
produced by a ventricular automaticity focus that suffers from an entrance block that is not irritable. not vulnerable to overdrive suppression