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82 Cards in this Set
- Front
- Back
What are some risk factors for sudden death
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syncope
late potentials T-wave alternans high grade ventricular ectopy non-sustained, sustained or inducible V-tach |
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What are the 3 causes(mechanisms) of Ventricular tachycardia
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automaticity
reentry triggered |
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Which type of mechanism is acute?
Which type of mechanism is chronic |
acute-automatic
chronic- reentry |
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Where anatomically do automatic arrhythmias occur?
Reentry? |
automatic- at the zone of infarction, d/t residual ischemia
Reentry- at the borders of the tachy zone, between the scar tissue and the healthy myocardium |
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Which mechanism is the most common?
Which is the least common? |
most-reentry
least-automatic |
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What are some causes of automatic?
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hypoxemia
electrolyte abnormalities acid-base imbalance increased adrenergic tone AMI within 48 hrs |
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What is the most common arrhythmia associated with automatic?
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multi focal A tach, common with acute pulm disease
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Name 4 common anti arrhythmics used to treat
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amiodarone- class III
lidocaine- 1b phenytoin- 1b bretylium- anti arrhythmic |
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Which mechanism is inducible in the EP lab?
Which is not? |
Reentry and triggered are inducible
Automatic is not inducible |
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Is a reentrant circuit permanent?
What about automatic? |
reentry-yes
automatic-no |
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Is underlying cardiac disease a mechanism for triggered or reentry?
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Not required for triggered, but yes for reentry
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What is sustained V tach?
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greater than 30 seconds
or greater than 10 beats |
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Which mechanism is monomorphic typically seen in?
polymorphic? |
monomorphic is with reentry or triggered
polymorphic is with automatic or triggered |
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Can you ablate polymorphic V-tach?
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no
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What are the two distinct clinical syndromes of triggered vent activity?
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pause dependent
catechol dependent |
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For pause dependent..
what phase of AP? EAD or DAD? What electrolytes? |
downslope phase 3
EAD hypokalemia, hypomagnesmia |
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What high risk ECG element is associated with pause-dependent, thus making it pause dependent. What arrhythmia is it associated with?
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long QT
torsades |
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What ECG finding is associated with EAD
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U wave or distorted T wave
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The longer the CL of the previous, the (more/less)exaggerated the TU aberration.
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more
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What are somethings that put patients at risk for pause dependent?
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hypokalemia, hypomagnesmia
heart blocks > in women class 1a or III anti-arrhy. anti microbials antifungal antimalarial anti histamine GI prokinetic Psychoactive anti-HIV (pentamidine) Dig toxicity (chronic afib) procainamide (proarrhythmic) |
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What phase is associated with catechol dependent
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phase 4
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Which is associated with congenital long QT?
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catechol dependent
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Which group do these belong in.. DADS, increased Calcium in cytosol, monomorphic.
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catechol dependent
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Calcium dependent ventricular activity occurs during an increase in (sympathetic/parasympathetic) tone
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sympathetic
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How do you treat catechol dependent activity?
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Beta blockers
class I agents verapamil |
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Which type of V tach can be studied and ablated?
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monomorphic
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What type of pacing do you use to induce V tach?
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programmed extra stimulus
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What are most clinical V tach from?
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reentrant around a scar
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Why do we study Vtach
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confirm inducibility and reentrant nature of rhythm
test efficacy of antiarrhythmics map focus to direct ablation test easibility of anti-tach devices |
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Describe the difference in conduction and refractory periods with the alpha and beta limbs of the reentrant circuit
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alpha has slow conduction and fast refractory
beta has fast conduction and slow refractory |
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What catheters are used in Vt induction
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RVA (or reposition to RVOT)
HIS HRA LVA (rarely used) |
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When inducing VT how many extra stimuli and how many CL's
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up to 3 extra stimuli and 3 CL's
> than 3 PES is aggressive |
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What can you do if you complete protocol and don't induce VT
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reposition to RVOT and repeat, give isuprel and repeat
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Where in the heart is VT when pacing in the RVA
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mid RV and LV apex
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where in the heart is VT when pacing in the RVOT
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LV base or RVOT
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What cycle length should you never go below? and why
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<200 msec, because at risk for nonclinical VT or VF (healthy myocardium will induce)
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How can you tell if you are pacing in RVA or RVOT, what does lead II look like in both, what type of axis and BBB for both
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RVA pacing- lead II neg, RBBB w/ left axis
RVOT pacing- lead II positive, LBBB w/ inferior axis |
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Why do we want to know the VERP? What is it?
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to access refractoriness of ventricular tissue
it is the longest coupling interval that blocks the beat |
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What percent of the population does not have retrograde conduction?
what happens if they don't |
30%, can't do study
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How do you check for retrograde conduction?
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pace in RVA until 1:1 conduction is lost, will have VH but no A
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If you have no VA wencke at 250 msec, what does that mean?
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Impulse probably getting to atria via another pathway, WPW, accessory
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What is the significance of VERP?
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ability to conduct and maintain arrhythmias
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What do you need to do when you induce VT?
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get 12 lead
record it tell stimulator cycle length so they know how to pace terminate |
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What type of VT do you synchronize cardiovert, what type do you defibrillate?
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synch- monomorphic > 200msec
defib-polymorphic or faster than 200msec |
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What is the criteria to determine VT vs. wide SVT
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For VT..inducibility from ventricle not atria
QRS morphology atypical of BBB or pre-excitation No response to adenosine AV dissociation |
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How do you determine AV dissociation with VT?
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Pace in atria, at faster rate than ventricle's VT, if it entrains the rhythm than it is originating from atria, if not then you have AV dissociation
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What information do you want to know when you are documenting VT?
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cycle length
hemodynamic effects morphology axis |
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How can you tell if it is BBB or VT?
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If it is reentrant BB VT... ..then you need a clear HIS, you would have H
another catheter to read RBB add PES during VT to disturb and compare VH intervals with and without PES, one constant, one variable may respond to adenosine b/c AV node is involved |
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What is BB VT associated with and what is it?
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seen with LV dilation and partial or complete LBBB w/ long PRI in NSR
It is a macro reentrant circuit around 2 sides of intraventricular septum |
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How do you treat BB VT?
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ablate RBBB
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How can you terminate V tach
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synch cardioversion or defibrillate, pre-med patient with versed or wait until unconscious
Pace terminate |
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How do you pace terminate
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burst pacing 8-12 beats @ CL 10-20 msec faster than VT to entrain then stop
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How many joules do you need for monophasic?
for biphasic? |
mono-300-360 joules
bi-200 joules |
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What is the ultimate treatments for VT?
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AICD
ablation of slow well tolerated V tachs |
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If you have an S1 and S2 what are you looking for?
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ERP
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If you are looking for ERP how do you know if it is AERP, AVNERP or VERP
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if AERP or AVNERP than pacing in atria
if VERP than pacing in ventricle |
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If you see S2, S3, S4 then what are you looking for?
If in atria and if in ventricle? |
if in atria then SVT
if in ventricle than VT or SVT |
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What type of pacing does SNRT use?
What do you have..S1, S2, S3, S4 |
continuous
only S1 |
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what type of pacing does AV wenke and VA wenke use?
What do you have..S1, S2, S3, S4 |
continuous
only S1 |
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what type of pacing is extrastimulus for?
What do you have S1, S2, S3, S4 |
ERP's
only S1 and S2 |
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For syncope what is the least responsible?
the most? |
least-bradycardias
most-vasodepressors |
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What does cardiac disease and V tach get you?
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sudden death
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What is EAD associated with?
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triggered
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Is automatic inducible?
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no
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Is reentrant inducible?
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yes
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PA
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25-55 ms
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AH
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55-125 ms
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HBE
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<30 msec
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HV
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35-55 msec
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QRS
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80-110 msec
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QTc
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</= 450 msec for men
</= 470 msec for women |
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QTc formula
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QT/ sq rt of mean RR(sec)
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SNRT
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<1500 msec
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CSNRT
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<525 msec
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SACT
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50-125 msec
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AERP
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180-330 msec
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AVERP
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230-450 msec
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AVFRP
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330-550 msec
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VERP
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170-290 msec
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AV wenke
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</= 450 msec
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VA wenke
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380-400 msec
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CSNRT formula
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SNRT- BCL
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