Conduction: Difference between revisions

→‎The PQ interval: added that PQ/PR prolongation can be caused by increased vagal tone or pharmacologically induced
(→‎The PQ interval: noted that PQ interval is sometimes referred to as the PR interval as the Q wave is not always present)
(→‎The PQ interval: added that PQ/PR prolongation can be caused by increased vagal tone or pharmacologically induced)
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'''The normal PQ interval is between 0.12 and 0.20 seconds'''.
'''The normal PQ interval is between 0.12 and 0.20 seconds'''.


A prolonged PQ interval is a sign of a degradation of the conduction system. This is called [[Arrhythmias#Atrioventricular_block|1st, 2nd or 3rd degree AV block]].
A prolonged PQ interval is a sign of a degradation of the conduction system, increased vagal tone (Bezold-Jarisch reflex), or it can be pharmacologically induced.  
 
This is called [[Arrhythmias#Atrioventricular_block|1st, 2nd or 3rd degree AV block]].


A short PQ interval can be seen in the [[Arrhythmias#WPW_syndrome|WPW syndrome]] in which a faster connection exists between the atria and the ventricles.
A short PQ interval can be seen in the [[Arrhythmias#WPW_syndrome|WPW syndrome]] in which a faster connection exists between the atria and the ventricles.