Abnormal EKGs Flashcards
What is ventricular tachycardia?
a run of 3 or more PVC
What is atrial trigeminy?
premature atrial beat after end of 2 normal cycles, repeatedly
What foci in the heart are good at sensing low O2?
ventricular automaticity foci
this can be caused by poor coronary blood supply! (MI)
What is aberrant ventricular conduction and when do you see it?
slightly widened QRS wave seen after a premature atrial beat
bc one of the bundle branches is not completely repolarized; temporarily refractory to depolarization
What type of murmur is associated with runs of VT and PVCs, yet is considered benign?
mitral valve prolapse
What is PAT and what does it look like?
paroxysmal atrial tachycardia
150-250 bpm w/ P’ waves that don’t look normal w/ normal QRS waves following
What will you see on an EKG in a junctional escape rhythm?
rate of 40-60 bpm
will see series of lone QRS complexes
can see retrograde inverted P’ waves immediately before QRS, after QRS, or buried w/in each QRS
What is escape rhythm?
automaticity focus escapes overdrive suppression to pace at its inherent rate:
atrial escape rhythm
junctional escape rhythm
ventricular escape rhythm
What is a PVC and what does it look like?
irritable ventricular focus (usually caused by hypoxia/ischemia) may suddenly fire
will see very wide and tall QRSs that are opposite normal polarity
pause after PVC, but not caused by resetting
What can make an atrial or junctional focus irritable?
adrenaline increased sympathetic stimulation excess digitalis, some toxins, ethanol hyperthyroidism stretch to some extent low O2
What rate range is paroxysmal tachycardia?
flutter?
fibrillation?
150-250
250-350
350-450
What happens in sinus arrest?
SA node ceases pacing –> automaticity focus will escape and take over –> escape rhythm
What disease do you see multifocal atrial tachycardia in?
COPD
What is R on T phenomenon?
when a PVC hits on a T wave –> dangerous arrhythmias
occurs in hypoxia or low potassium
What is a junctional escape rhythm?
sinus arrest or block in proximal end of AV node–> auto focus in AV junction becomes active pacemaker –> junctional escape rhythm of 40-60 bpm
What is junctional bigeminy?
Junctional trigeminy?
premature junctional beat after one normal cycle, repeatedly
premature junctional beat after two normal cycles, repeatedly
What would you see in a non-conducted premature atrial beat?
too-early, unusual P’ wave that has no QRS-T response
What is sinus arrhythmia?
normal physiological mechanism; will see identical, normal P waves, with rate that gradually increases and gradually decreases
What is a premature junctional beat and what does it look like?
irritable automaticity focus in AV junction suddenly fires prematurely
will see early p wave and a widened QRS = aberrant ventricular conduction
can see inverted P’ waves before or after QRS
What does a premature atrial beat look like?
will see early P’ wave that looks different –> normal QRS
too-tall T wave
What is mobitz type II second-degree AV block?
lower down that mobitz type I/wenkebach
will see that intermittent non-conducting P waves, but no lengthened PR complexes before or after (kinda random)
What is stokes-adams syndrome?
total failure of SA node and all foci above ventricles –> have ventricular escape rhythm that is so slow you get syncope and have to monitor pt’s airway
What characterizes atrial fibrillation?
continuous rapid-firing of multiple atrial automaticity foci –> also see irregular QRS bc only random atrial depolarizations will reach the ventricles
Why are ventricular escape beats not so uncommon?
parasympathetic innervation inhibits SA node, atrial, and junctional foci –> burst of excessive PS activity can depress them all too much –> ventricular foci will make an escape beat
What does parasystolic mean?
when an automaticity focus has entrance block –> insensitive to passive depolarization but has own inherent pattern that can’t be overdrive-suppressed
What is second-degree AV Wenckebach (mobitz type I) block?
PR intervals become progressively longer until one QRS complex is dropped
block is higher up than mobitz type II block
What do frequent unifocal PVCs indicate?
poor oxygenation of a single ventricular focus
How many PVCs is considered pathological?
6 or more per minute
What happens in sinus block?
SA node misses one pacing cycle –> transient pause –> escape beat by an automaticity focus
What is atrial bigeminy?
premature atrial beat after end of one normal cycle, repeatedly
What characterizes multifocal atrial tachycardia?
arrhythmia of COPD, see HR over 100 bpm; each individual atrial focus paces at its own inherent rate –> rapid, irregular rhythm
What occurs to create a ventricular escape rhythm?
conduction block high in ventricle, but below AV node –> ventricular focus escapes to pace at 20-40 bpm
What is an escape beat?
automaticity focus transiently escapes overdrive suppression to emit one beat
atrial, junctional, or ventricular
What is Ventricular parasystole and what does it look like?
a ventricular auto focus has entrance block –> paces at its own inherent rate
will see a PVC coupled to a long series of normal cycles (essentially 2 rhythms, one from SA node, one from spot in ventricle)
What is wandering pacemaker?
irregular rhythm produced by the pacemaker activity wandering from SA node to nearby atrial automaticity foci –> cycle length and P wave shape variation
What are multifocal PVCs caused by and what do they look like?
caused by severe hypoxia in multiple ventricular foci –> see diff looking PVCs at diff rates
This is very serious!
