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 (preexcitation). 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



Sudden cardiac death in paediatric patients with WPW syndrome

  A recent multicenter study including 912 WPW syndrome patients (21 years-old or younger patients) showed that the presence of at least one of the below factors increases the risk of experiencing a life threatening event:
- Male sex
- Ebstein malformation
- Inducibility of atrial fibrillation during electrophysiological study
- Rapid anterograd conduction: shortest pre-excited RR interval in atrial fibrillation <250 milliseconds or shortest paced cycle length with pre-excitation during atrial pacing <250 milliseconds.
- Presence of more than one accessory pathway



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: (including links to abstract and/or full-text articles)

  JACC Clin Electrophysiol 2018;4(4):433-444.

  Arrhythm Electrophysiol Rev 2018;7(1):32-38.

  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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ECG 9a. The ECG above belongs to a 46 years-old man with mild mitral stenosis and frequent attacks of palpitation.
At first glance, the q waves in inferior leads and tall R waves in lead V1 suggest a diagnosis of old inferoposterior
myocardial infarction. The delta waves in some patients with WPW syndrome may imitate q waves suggesting old myocardial
infarction.
In the above ECG, lead V3 shows a giant delta wave, while leads V4 and aVL show subtle delta waves.

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ECG 9b. The above ECG was recorded during one of his palpitation attacks.
During the tachycardia, AV-node, His bundle and Purkinje fibers are used for conduction to the ventricles
and the accessory pathway is used for re-exciting the atria: orthodromic AVRT (AV Reciprocating Tachycardia).
Because of this, delta wave is not seen during the tachycardia.
Because of this, leads III and aVF do not show Q waves (delta wave) during the tachycardia.
Because of this, tall R wave in lead V1 is not seen during the tachycardia.
Because of this, the ECG above looks very similar to the post-ablation resting ECG below (ECG 9c).

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ECG 9c. Electrophysiologic study showed left posterolateral accessory pathway in this patient.
The above ECG was recorded after ablation of the accessory pathway.
Inferior leads do not show q waves anymore. No more suggestion of old inferoposterior myocardial infarction.
Lead V3, V4 and aVL also do not show delta waves any more.

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ECG 10. The ECG above belongs to a 3 years-old child. Delta waves and PR interval shortening are absent in some beats:
intermittent WPW syndrome. Sinus arrhythmia and basaline drift are also seen.

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




ECG 11. The ECG above belongs to a 55 years-old woman with ischemic cardiomyopathy. She has 3-vessel (extensive)
coronary artery disease. She had undergone coronary artery bypass graft surgery 2 years ago.
ECHOcardiography showed left ventricular systolic dysfunction with an Ejection Fraction of 30%.
The QRS complexes are not wide and there is left bundle branch block pattern.
The initial r wave of the rR' in lead I gives the impression of delta wave, at first glance.
However, it is not a delta wave since the PR interval is NOT shortened.

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ECG 12. The ECG above is from a 40 years-old woman.
Sinus rhythm, left bundle branch block, short PR interval and delta waves are seen.

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ECG 13. The ECG above is from a totally asymptomatic 39 years-old man.
Short PR interval and delta waves are seen: WPW syndrome.
Although it mimicks old inferior wall myocardial infarction at first glance, his ECHOcardiogram was normal.

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ECG 14a. The ECG above is from a 46 years-old man with moderate mitral stenosis.
He is totally asymptomatic: no dyspnea, no chest pain.
PR interval shortening with Delta waves are clearly seen: WPW syndrome.
The heart rate is 97/minute. At this rate, leads V2 to V6, I and aVL show ST segment depression.
Leads III and aVR show ST segment elevation.

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ECG 14b. Above ECG belongs to the same man. It was recorded one day after ECG 14a.
The patient ingested 40mg Propanolol 90 minutes before recording of the above ECG.
Slowing of the heart rate by Propranolol was attempted to make reliable Doppler evaluation of the mitral valve.
Now the rhythm is sinus bradycardia with a rate of 42/minute.
At this heart rate, ST segment elevations and depressions are not seen anymore.
The ST segment deviations seen in ECG 14a were rate-dependent.
Be careful when evaluating ST segment deviations in patients with WPW syndrome.
It is well-known that treadmill exercise test is not a reliable diagnostic tool in patients with WPW syndrome.

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ECG 15. The ECG above belongs to a 39 years-old man with Wolff-Parkinson-White syndrome
Almost all leads show delta waves, including the leads III and aVF.
At first glance, the delta waves in III and aVF may suggest the diagnosis of old inferior wall myocardial infarction.
However, the delta waves in this patient mimick q waves suggesting old inferior myocardial infarction.
In fact, he has not experienced acute inferior wall myocardial infarction in the past.

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ECG 16a. The ECG above is from a one year-old infant who had experienced cardiac arrest, recently.
Delta waves with short PR interval are seen: WPW syndrome.

Pediatric Cardiologist Prof. Dr. Tevfik Karagoz has donated the above ECG to our website.

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ECG 16b. The above ECG belongs to the same infant with WPW syndrome.
Delta waves with short PR interval are seen.
The above ECG was recorded at cardiac catheterization laboratory, just before the ablation of her accessory pathway.

Pediatric Cardiologist Prof. Dr. Tevfik Karagoz has donated the above ECG to our website.

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ECG 16c. The above ECG belongs to the same infant.
The above ECG was recorded immediately after successful ablation of her accessory pathway.
No delta waves, no PR interval shortening.

Pediatric Cardiologist Prof. Dr. Tevfik Karagoz has donated the above ECG to our website.

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ECG 17. Above ECG is from a 9 years-old boy.
Delta waves and short PR interval is seen. The rhythm is sinus arrhythmia.
Electrophysiological study showed left lateral accessory pathyway.

Pediatric Cardiologist Prof. Dr. Tevfik Karagoz has donated the above ECG to our website.

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ECG 18. WPW pattern and left ventricular hypertrophy.
Delta waves and short PR interval is seen.
Above ECG is from a 36 years-old man with WPW syndrome and hemodynamically significant aortic valve stenosis.
ECHOcardiographically measured mean systolic aortic valve gradient was 51 mmHg.
His left ventricle was hypertrophic. The interventricular septal thickness was measured as 1.5 cm.

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ECG 19. Above is an ECG from a 27 years-old man with a normal ECHOcardiogram.
Delta waves and short PR interval is seen.

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