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Intraventricular Conduction: Difference between revisions
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→Left Posterior Fasicular Block (LPFB)
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|Supervisor= | |Supervisor= | ||
}} | }} | ||
=Conduction delay= | |||
[[Image:geleidingssysteem.jpg|thumb| If the conduction system is dysfunctional, the QRS widens beyond 0.12 seconds.]] | [[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 one of the bundle branches: | If the QRS complex is wider than 0.12 seconds this is mostly caused by a delay in the conduction tissue of one of the bundle branches: | ||
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*[[#Left_Posterior_Fasicular_Block_.28LPFB.29| Left posterior fascicular block (LPFB)]] | *[[#Left_Posterior_Fasicular_Block_.28LPFB.29| Left posterior fascicular block (LPFB)]] | ||
Sometimes this conduction delay is ''' | Sometimes this conduction delay is '''rate-dependent ''': the bundle branch block occurs only at higher heart rates and disappears at slower heart rates. | ||
{{clr}} | {{clr}} | ||
= LBBB vs RBBB = | |||
[[Image:LBTB_RBTB_en.png|thumb| A bundle branch block causes a delay in the depolarization of the right (RBBB) or left (LBBB) ventricle. In RBBB the QRS complex shows a second peak or R' in V1.]] | [[Image:LBTB_RBTB_en.png|thumb| A bundle branch block causes a delay in the depolarization of the right (RBBB) or left (LBBB) ventricle. In RBBB the QRS complex shows a second peak or R' in V1.]] | ||
Check V1 when QRS > 0.12 sec. | Check V1 when QRS > 0.12 sec. | ||
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{{clr}} | {{clr}} | ||
=Left Bundle Branch Block (LBBB)= | |||
{{:LBBB}} | {{:LBBB}} | ||
{{clr}} | {{clr}} | ||
=Right Bundle Branch Block (RBBB)= | |||
{{:RBBB}} | {{:RBBB}} | ||
=Left Anterior Fascicular Block (LAFB)= | |||
{{Box| | {{Box| | ||
;Criteria for | ;Criteria for Left Anterior Fascicular Block | ||
#Frontal plane axis between −45° and −90°. | |||
#qR pattern in lead aVL. | |||
#R-peak time in lead aVL of 45 ms or more. | |||
#QRS duration less than 120 ms. | |||
These criteria do not apply to patients with congenital heart disease in whom left-axis deviation is present in infancy. | |||
}} | }} | ||
[[Image:LAHB.png|thumb|Left anterior hemiblock]] | [[Image:LAHB.png|thumb|Left anterior hemiblock]] | ||
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{{clr}} | {{clr}} | ||
=Left Posterior Fasicular Block (LPFB)= | |||
[[File:E0003194.png|thumb|A patient with [[RBBB]] and left posterior Fascicular block]] | |||
{{Box| | {{Box| | ||
;Criteria for posterior fascicular block: | ;Criteria for posterior fascicular block: | ||
#Frontal plane axis between 90° and 180° in adults. Owing to the more rightward axis in children up to 16 years of age, this criterion should only be applied to them when a distinct rightward change in axis is documented. | |||
#rS pattern in leads I and aVL. | |||
#qR pattern in leads III and aVF. | |||
#QRS duration less than 120 ms. | |||
:Right ventricular [[hypertrophy]] and previous [[Ischemia#Lateral|lateral myocardial infarction]] have been excluded | :Right ventricular [[hypertrophy]] and previous [[Ischemia#Lateral|lateral myocardial infarction]] have been excluded | ||
}} | }} | ||
=Mechanisms of aberrant conduction= | |||
[[Image:E000573.jpg|Rate dependant left bundle branch aberration|thumb]] | |||
{{box| | {{box| | ||
;Aberrant ventricular conduction is defined as | ;Aberrant ventricular conduction is defined as | ||
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{{clr}} | {{clr}} | ||
{{Box| | {{Box| | ||
=References= | |||
<biblio> | <biblio> | ||
#Garcia isbn=0763722464 | #Garcia isbn=0763722464 | ||