Conduction: Difference between revisions

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==The PQ time==
==The PQ interval==
  The PQ time starts at the beginning of the atrial contraction and ends at the beginning of the ventricular contraction.
  The PQ interval starts at the beginning of the atrial contraction and ends at the beginning of the ventricular contraction.
  [[Image:QRSwaves.jpg|thumb]]
  [[Image:QRSwaves.jpg|thumb]]


The PQ time indicates how fast the action potential is transmitted through the AV node (atrioventricular) from the atria to the ventricles. Measurement should start at the beginning of the P wave to the beginning of the QRS segment.
The PQ interval indicates how fast the action potential is transmitted through the AV node (atrioventricular) from the atria to the ventricles. Measurement should start at the beginning of the P wave to the beginning of the QRS segment.


'''The normal PQ is between 0.12 and 0.20 seconds'''.
'''The normal PQ interval is between 0.12 and 0.20 seconds'''.


A prolonged PQ time is a sign of a degradation of the conduction system. This is called [[Arrhythmias #AV-block|1st, 2nd or 3rd degree AV block]].
A prolonged PQ interval is a sign of a degradation of the conduction system. This is called [[Arrhythmias #AV-block|1st, 2nd or 3rd degree AV block]].


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