Conduction: Difference between revisions

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[[Image:QRSwaves.jpg|thumb|300px|right]]
[[Image:QRSwaves.jpg|thumb|300px|right]]
==The PQ interval==
==The PQ interval==
The PQ interval 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:PR_interval_buildup.svg|thumb|The PR duration depends on the conduction velocity in the atria, AV node, His bundle, bundle branches and Purkinje fibers.]]
[[Image:PR_interval_buildup.svg|thumb|The PR duration depends on the conduction velocity in the atria, AV node, His bundle, bundle branches and Purkinje fibers.]]


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==The QRS duration==
==The QRS duration==
The QRS duration indicates how fast the ventricles depolarize.  
'''The QRS duration indicates how fast the ventricles depolarize.'''


The ventricles depolarize  normally within 0.10 seconds. When this is longer than 0.12 seconds, this is a [[conduction delay| conduction delay]]. Possible causes of a QRS duration > 0.12 seconds include:
The ventricles depolarize  normally within 0.10 seconds. When this is longer than 0.12 seconds, this is a [[conduction delay| conduction delay]]. Possible causes of a QRS duration > 0.12 seconds include: