SA-exit-blok: verschil tussen versies
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{{Chapter|Sinusritme en | {{Chapter|Sinusritme en sinusaritmie}} | ||
[[Image:sa_exit_blok.jpg|thumb|Sino-atrial exit block (more precisely: type II second degree SA exit block)]] | [[Image:sa_exit_blok.jpg|thumb|Sino-atrial exit block (more precisely: type II second degree SA exit block)]] | ||
[[Image:sa_exit_blok2.png|thumb|Sino-atrial exit block]] | [[Image:sa_exit_blok2.png|thumb|Sino-atrial exit block]] | ||
Versie van 7 feb 2009 22:54
| Dit is onderdeel van: Sinusritme en sinusaritmie |
During sino-atrial exit block, the depolarizations that occur in the sinus node cannot leave the node towards the atria. They are blocked. On the ECG this is expressed as a pause. SA exit block can be destinguished from sinusarrest because the pause in SA exit block is a multiple of the P-P interval that preceded the pause.
Three subtypes can be destinguished:[1]
- Type I second degree (Wenkebach) SA exit block: the P-P interval progressively shortens prior to the pause
- Type II second degree SA exit block: the pause equals approximately 2-4 times the preceding PP interval
- Third degree SA exit block: absence of P waves (can only be diagnosed with an sinus node electrode, during electrophysiological evaluation)