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37 Cards in this Set
- Front
- Back
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SA Node |
continuously regulates the heart rate according to the body's fluctuating needs |
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Sick Sinus Syndrome |
most common bradyarrhythmia |
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EP study may helpful if: |
symptoms have not been documented with bradycardia |
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Sinus Node Recovery Time |
the test designed to assess SA nodal automaticity in the EP lab |
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Measurement of the SNRT is based on the phenomenon of: |
overdrive suppression |
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SNRT |
measured from the last paced beat to the next spontaneous sinus beat; longest recovery interval |
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normal value for SNRT |
1500 ms |
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equation for CSNRT |
SNRT - BCL
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normal CSNRT |
525 ms |
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Sinoatrial Conduction Time (SACT) |
test meant to assess how well the SA node is ale to conduct the electrical impulses it produces out to surrounding atrial tissue |
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half the difference between the return cycle and the BCL |
SACT |
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Return Interval equation |
BCL + 2SACT |
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SA node |
group of pacemaker cells surrounded by a rim of perinodal tissue |
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Normal SACT |
50-125ms |
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vasovagal syncope |
parasympathetic response often secondary to sympathetic influence |
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may induce parasympathetic block with: |
atropine |
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symptoms of AV nodal block |
lightheadedness, syncope, pre syncope, dizziness |
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Ischemia and MI are common causes of this: |
HIS-Purkinje block |
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1st degree |
usually at the level of the AV node |
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2nd degree |
intermittent conduction |
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Mobitz II |
usually infra nodal |
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3rd degree |
usually infra nodal if acquired |
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a wide QRS usually indicates the block is: |
infranodal |
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Exercise/isoproterenol |
improves AV nodal; infranodal conduction ratio may worsen |
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atropine |
improves AV nodal; infranodal conduction arate may worsen |
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Vagal maneuvers |
worsens AV nodal; no change infra nodal |
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Beta Blockers |
worsens AV nodal; no change infra nodal |
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normal AH |
50-120 ms |
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normal HV interval |
35-55 ms |
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HV > 100 ms |
an indication for a pacemaker |
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HIS > 25 ms |
abnomal |
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Typical Mobitz I |
prolong AH |
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Typical Mobitz II |
always indicates distal conducting system disease |
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The S1-S2 coupling interval that produces block in the AV node is its: |
ERP |
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the shortest H1-H2 interval attained |
FRP |
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Block in His-Purkinje |
>400ms, needs a pacer |
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incremental pacing |
long drive trains at a constant cycle length, rates increased with each sequence |
