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7 Cards in this Set
- Front
- Back
The AV node holds each sinus impulse longer that normal before conducting it through the ventricles. Each impulse is eventually conducted. Once into the ventricles, conduction proceeds normally.
More of a delay than a block due to the PR interval being > .20 or 5 blocks |
first degree heart block
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As the sinus node initiates impulses, each one is delayed in the AV node a little longer than teh preceding one, until one is eventually blocked completly. Those impulses that are conducted travel normally through the ventricles.
progressively longer PR intervals and then miss a QRS complex |
second degree mobitz type one wenckebach
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The AV node selectively conducts some beats while blocking others. Those that are not blocked are conducted through to the ventricles, although they may encounter a sloght delay in the node. Once in the ventricles, conduction proceeds normally.
>p waves that QRS complexes PR intervals on conducted beats will all be the same often rhythm is regular with conduction ratio constant v/s variable |
second degree mobitz type two classic
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The block at the AV node is complete. The sinus impulses cannot penetrate the node, and thus are not conducted through to the ventricles. An escape mechanism from either the junction or the ventricles will take over to pace the ventricles. The atria and the ventricles function in a totally disssociated fashion.
p waves line up as well as QRS's just not together |
complete heart block or
third degree |
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The atria are so irritable thta a ultitude of foci initiate impulses, causing the atria to depolarize repeatedly in a fibrillatory manner. The AV node blocks most of the impulses, allowing only a limited number through to the ventricles.
typically irregular controlled is <100 bpm uncontrolled is >100 bpm these people have probly been diagnosed with heart failure and are on blood thinners to prevent coagulation |
atrial fibrillation
a-fib |
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A single irritable focus within the atria issues an impulse that is conducted in a rapid, repetetive fashion. To prevent the ventricles from receiving too many imulses, the AV node blocks some of the impulses from being conducted through to the ventricles.
typically regular looking for a conduction ratio of p waves to QRS's <100 bpm is controlled >100 bpm is uncontrolled |
atrial flutter
a-flutter |
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no p wave or an inverted p wave with a narrow QRS complex
<60 bpm =escape 60-100 bpm=accelerated >100 bpm =tachy |
junctional rhythms
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