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|editor= A. Bouhiouf, Msc | |editor= A. Bouhiouf, Msc | ||
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== | ==Conduction delay== | ||
[[Image:geleidingssysteem.jpg|thumb| | [[Image:geleidingssysteem.jpg|thumb| If the conduction system is dysfunctional, the QRS widens beyond 0.12 seconds.]] | ||
If the QRS complex is wider than 0.12 seconds this is mostly caused by a delay in the conduction tissue of on of the bundle branches: | |||
*[[# | *[[#LBTB| Left Bundle Branch Block (LBTB))]] | ||
*[[# | *[[#RBTB| Right Bundle Branch Block(RBTB)]] | ||
* | *Interventricular conduction delay | ||
A right or left axis rotation can be caused by a: | |||
*[[#Criteria | *[[#Criteria for LAFB| left anterior fascicular block (LAFB)]] | ||
*[[#Criteria | *[[#Criteria for LPFB| left posterior fascicular block (LPFB)]] | ||
Sometimes this conduction delay is '''frequency-depending''': the bundle branch block occurs only at higher heart rates and disappears at slower heart rates. | |||
{{clr}} | {{clr}} | ||
== | == LBTB vs RBTB == | ||
Watch V1 if QRS > 0,12 sec. | |||
If the last QRS activity in V1 is below the baseline (moving away from V1), than LBTB is the most likely diagnosis. | |||
If the last activity is above the baseline, it's a RBTB | |||
[[Image:Verschil_LBTB-RBTB.png|thumb| | [[Image:Verschil_LBTB-RBTB.png|thumb| A bundle branch block causes a delay in the depolarisation of the right (RBTB) or left (LBTB) ventricle. In RBTB the QRS complex shows a second peak or R' in V1.]] | ||
If the QRS > 0.12 sec. but you can't tell whether it's a RBTB or LBTB, than it's 'interventriculair conduction delay', which is allways right. If the conduction system is deteriorates further, the conduction can be taken over by the cardiomyocytes. The conduct the electrical signal cell-to-cell which results in a very wide QRS complex (> 0.16-0.20 seconds). | |||
{{clr}} | {{clr}} | ||
=== | ===LBTB=== | ||
Left bundle branch block | |||
QRS >0,12 sec met brede R in I aVL V5V6 en afwezige q aldaar. | QRS >0,12 sec met brede R in I aVL V5V6 en afwezige q aldaar. | ||
[[Image:Ontstaan_LBTB.png|thumb| Bij een linker bundeltakblok ontlaad de linker kamer ná de rechter kamer.]] | [[Image:Ontstaan_LBTB.png|thumb| Bij een linker bundeltakblok ontlaad de linker kamer ná de rechter kamer.]] |