Diagnostic criteria

  Delta wave: Using the accessory pathway, supraventricular impulse is not delayed by the AV node.

      This results in earlier onset of left ventricular depolarization.

      The premature depolarization is represented by the
delta wave.

  PR interval shortens : Since there is no physiological delay in the AV node, the PR interval shortens.

  QRS widens: The addition of delta wave to the QRS complex forms a wider QRS complex.


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 then appear again.



Other cardiac diseases which have been reported to show increased incidence of
WPW pattern on the surface ECG


  Hypertrophic cardiomyopathy

  Mitral valve prolapsus

  Ebstein's anomaly (may have multiple accessory AV pathways)

  Left ventricular hypertrabeculation / noncompaction




WPW Syndrome and treadmill exercise (stress) test

  ST segment depression is usually observed during treadmil exercise test of a patient with WPW syndrome.

      Therefore, observation of ST segment depression during exercise test does not support

      the diagnosis of coronary artery disease in this group of patients.

  In some patients with WPW syndrome, the Delta wave can disappear during the exercise test

      (especially in subjects with left-sided accessory pathyways).

  If delta wave disappears abruptly during exercise, it suggests that

      the acccessory pathway has a longer anterograde effective reftactory period.

  In some patients with no delta waves in resting ECGs, exercise test may bring on

      the delta wave and preexcitation.




References

  Am Heart J 78:13, 1969.

  Acta Med Scand (suppl)169:365, 1969.





ECG 1. Wolff-Parkinson-White Syndrome and
delta waves . The delta waves are formed by prematurely depolarized regions of
the ventricle. Since the
delta wave is superimposed on the terminal part of the PR interval, the PR interval seems to be
shortened.

Dr. Gulay Copur has donated this ECG to our website.

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ECG 2. WPW syndrome and
delta waves . Delta waves "steal" from the PR interval, resulting in wider QRS complexes.

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ECG 3. Another patient with WPW syndrome and
delta waves . The PR interval shortens and QRS complex widens.

This ECG has been donated by Prof. Dr. Remzi Karaoguz to our website.

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ECG 4a. WPW syndrome and
delta waves in a patent with hypertrophic (asymmetrical septal) cardiomyopathy.
If
the calibration of the ECG is 10mm/mV (normal calibration) it may be difficult to realize the delta waves.

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ECG 4b. The above ECG belongs to the same patient with a calibration of
20mm/mV . Delta waves can now be recognized
more easily.
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ECG 5a. WPW syndrome may cause false positive (falsely abnormal) treadmill exercise test results. There is no ST segment
depression in the pretest ECG above.

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ECG 5b. The ECG of the same patient after 2 minutes and 30 seconds of the start of the treadmil exercise test. There is no
obvious ST segment depression.

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ECG 5c. The ECG of the same patient at the third minute of the test shows
ST segment depression in leads I, II and C6 .

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ECG 5d. The ECG of the same patient after 4 minutes and 30 seconds shows
widespread ST segment depression .

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ECG 5e. The above ECG was recorded 30 seconds after the treadmil was stopped. The
ST segment depression , although less
pronounced, persist.

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ECG 5f. One minute and 30 seconds after the test, the ECG shows no ST segment depression.

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ECG 6a. The above ECG belongs to a 6-years old boy. The
Delta waves and PR interval shortening makes the diagnosis of
WPW syndrome.

Pediatric cardiologist Mahmut Gokdemir has donated the above ECG to our website.

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ECG 6b. The above ECG belongs to the same boy and was recorded during the "palpitation".
The heart rate is about 300/minute.

Pediatric cardiologist Mahmut Gokdemir has donated the above ECG to our website.

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ECG 7. 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 8. 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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