WPW syndrome may be intermittent

  In some patients, preexcitation may be seen on occasional days.

  In some others, preexcitation may appear in a few beats and then disappear and reappear again.

  In patients with complete AV block, some P waves buried in QRS complex, will deform the QRS and

      may falsely give the impression of
delta wave and therefore intermittent WPW syndrome

      at first glance.





ECG 1. Intermittent WPW syndrome. Only
some beats show short PR interval and delta waves while others do not.

Dr. Beatrice Brembilla has donated the above ECG to our website.

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ECG 2. WPW syndrome in an 11 years old child. Preexcitation was not observed everyday. Electrophysiological study revealed
inferior accessory pathyway and the child underwent successfull radiofrequency ablation. This ECG also shows sinus
arrhythmia.

Dr. Christian Balmer has donated the above ECG to our website.

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ECG 3. Intermittent WPW syndrome in child.
.

Dr. Christopher Rausch has donated the above ECG to our website.

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ECG 4. The left side of above ECG shows complete AV block.
P waves are not related to QRS complexes.
Some P waves, buried in the QRS, deform the QRS complex and give the impression of intermittent WPW syndrome at first glance

The right side shows Wenkebach AV block.
PR interval gradually prolongs; 3rd and 6th
P waves are dropped (not conducted to the ventricles).

Click here for a more detailed ECG