EKG changes with Wolff-Parkinson-White syndrome.12 lead EKG of individual with Wolff-Parkinson-White syndrome.
Find information on thousands of medical conditions and prescription drugs.

Wolff-Parkinson-White syndrome

Wolff-Parkinson-White syndrome (WPW) is a syndrome of pre-excitation of the ventricles due to an accessory pathway known as the Bundle of Kent. This accessory pathway is an abnormal electrical communication from the atria to the ventricles. more...

Waardenburg syndrome
Wagner's disease
WAGR syndrome
Wallerian degeneration
Warkany syndrome
Watermelon stomach
Wegener's granulomatosis
Weissenbacher Zweymuller...
Werdnig-Hoffmann disease
Werner's syndrome
Whipple disease
Whooping cough
Willebrand disease
Willebrand disease, acquired
Williams syndrome
Wilms tumor-aniridia...
Wilms' tumor
Wilson's disease
Wiskott-Aldrich syndrome
Wolf-Hirschhorn syndrome
Wolfram syndrome
Wolman disease
Wooly hair syndrome
Worster-Drought syndrome
Writer's cramp

The incidence of WPW syndrome is between 0.1 and 3 percent of the general population.,, While the vast majority of individuals with WPW syndrome remain asymptomatic throughout their entire lives, there is a risk of sudden death associate with WPW syndrome. Sudden death due to WPW syndrome is rare (incidence of ≤0.6%,), and is due to the effect of the accessory pathway on tachyarrhythmias in these individuals.


In normal individuals, electrical activity in the heart is initiated in the sinoatrial (SA) node (located in the right atrium), propagates to the atrioventricular (AV) node, and then through the bundle of His to the ventricles of the heart. (See electrical conduction system of the heart).

The AV node acts as a gatekeeper, limiting the electrical activity that reaches the ventricles of the heart. This is an important function of the AV node, because if the signals generated in the atria of the heart were to increase in rate (such as during atrial fibrillation or atrial flutter), the AV node will limit the electrical activity that conducts to the ventricles. For instance, if the atria are electrically activated at 300 beats per minute, half those electrical impulses are blocked by the AV node, so that the ventricles are activated at 150 beats per minute (giving a pulse of 150 beats per minute). Another important property of the AV node is that it slows down individual electrical impulses. This is manifest on the EKG as the PR interval, the time from activation of the atria (manifest as the P wave) and activation of the ventricles (manifest as the QRS complex).

Individuals with WPW syndrome have an accessory pathway that connects the atria and the ventricles, in addition to the AV node. This accessory pathway is known as the bundle of Kent. This accessory pathway does not share the rate-slowing properties of the AV node, and may conduct electrical activity at a significantly higher rate than the AV node. For instance, in the example above, if an individual had an atrial rate of 300 beats per minute, the accessory bundle may conduct all the electrical impulses from the atria to the ventricles, causing the ventricles to activate at 300 beats per minute. The ventricles are not capable of activating in a uniform manner at rates that fast and will fibrillate instead (ventricular fibrillation). If not corrected rapidly, ventricular fibrillation leads to sudden cardiac death (SCD).

Read more at Wikipedia.org

[List your site here Free!]

Bifascicular block and Wolff-Parkinson-White syndrome - Electrocardiogram of the Month
From CHEST, 7/1/90 by Peter Rakovec

The casual coexistence of ventricular preexcitation with either right or left bundle branch block has been reported by several authors.[1-4] The resulting electrocardiographic pattern is quite different, if the accessory pathway is located in the same side of the heart where the bundle branch block exists, or in the opposite side of the heart. In the former case, the bundle branch block is considered ipsilateral to the anomalous pathway, and in the latter, it is considered to be contralateral. Ipsilateral bundle branch block is masked when preexcitation is present and can be seen occasionally in the electrocardiogram only if the preexcitation is intermittent. The association of preexcitation and contralateral bundle branch block results in wide QRS complexes showing both delta waves and terminal slowing. An unusual combination of bifascicular block and Wolff-Parkinson-White syndrome forms the basis of this report.


The patient, a 52 year-old-woman with ischemic heart disease, had attacks of tachycardia since 1980. In the same year, the Wolff-Parkinson-White syndrome was diagnosed from surface electrocardiogram and confirmed by electrophysiologic study, which revealed a left-sided accessory pathway. In 1982, right bundle branch block was seen for the first time. On admission, the patient had orthodromic tachycardia 180 beats/min and right bundle branch block. She had nausea and was hypotensive. The attack was terminated by administration of amiodarone 300 mg intravenously. On x-ray examination, the heart silhouette was diffusely enlarged.

During the following days electrocardiograms showed two different patterns, which can be seen in Figures 1 and 2. One pattern (Fig 1) is consistent with right bundle branch block and left anterior hemiblock, and the other (Fig 2) with right bundle branch block and Wolff-Parkinson-White syndrome.


It is evident from both electrocardiographic tracings (Fig 1 and 2) that the patient had right bundle branch block. The electrocardiogram in Figure 1 shows additional features of the left anterior hemiblock. The latter can be diagnosed utilizing the following two criteria: (1) left axis deviation, and (2) delay of the intrinsicoid deflection in lead aVL. The delay in the intrinsicoid deflection in aVL that is not detected in [V.sub.6] is called "regional delay" and is, if found associated with left axis deviation, specific for left anterior hemiblock.[5] In our case, both criteria are fulfilled. The association of right bundle branch block and one of the left hemiblocks is often called bifascicular block.

The electrocardiogram in Figure 2 shows right bundle branch block only; the signs of left anterior fascicular block are missing. Since the conduction abnormalities can be intermittent, the first impression could be that the left anterior hemiblock is present only occasionally. A closer look at this electrocardiogram, however, reveals signs of ventricular preexcitation (Wolff-Parkinson-White syndrome). Note the short PR interval and the delta wave. The QRS complexes are wide both due to preexcitation and due to right bundle branch block, which persists during preexcitation. The electrophysiologic criteria for co-existence of preexcitation and contralateral bundle branch block were published elsewhere.[4]

The association of bundle branch block and preexcitation is rare, since these two conduction abnormalities have different pathoanatomic substrates.[1,2]

In Wolff-Parkinson-White syndrome an accessory pathway bypasses the normal conduction pathway through the atrioventricular node, His bundle and its branches, and preexcites a portion of the ventricle. It has been shown that the prexcitation obscures the electrocardiographic pattern of the branch block, if it is ipsilateral to the accessory pathway.[2,3] Thus, in our case, the persistence of the right bundle branch block during preexcitation is indirect evidence of the fact that the accessory pathway is contralateral to the branch block, ie, left-sided. We reach the same conclusion by analyzing the delta wave polarity.[6] We see, however, that the conduction through the accessory pathway--intermittent in our patient--obscures the signs of left anterior hemiblock. The left ventricle is at least partly activated by the depolarization wave coming through the accessory pathway and the conduction delay due to left anterior fascicular block has no effect on the electrocardiographic pattern.


[1] Pick A, Fisch C. Ventricular preexcitation (WPW) in the presence of bundle branch block. Am Heart J 1958; 55:504-12

[2] Denes P, Goldfinger P, Rosen KM. Left bundle branch block and intermittent type A preexcitation. Chest 1975; 68:356-58

[3] Rakovec P, Kranjec I, Fettich JJ. Association of an accessory pathway and ipsilateral bundle branch block. Int J Cardiol 1985; 7:161-64

[4] Rakovec P, Kranjec I, Fettich JJ, Jakopin J, Fidler V, Turk J. Wolff-Parkinson-White syndrome type B and left bundle-branch block: Electrophysiologic and radionuclide study. Clin Cardiol 1985; 8:51-6

[5] Horwitz S, Lupi E, Hayes J, Frishman W, Cardenas M, Killip T. Electrocardiographic criteria for the diagnosis of left anterior fascicular block. Chest 1975; 68:317-20

[6] Gallagher JJ, Pritchett ELC, Sealy WC, Kasell J, Wallace AG. The preexcitation syndromes. Prog Cardiovasc Dis 1978; 20:285-327

COPYRIGHT 1990 American College of Chest Physicians
COPYRIGHT 2004 Gale Group

Return to Wolff-Parkinson-White syndrome
Home Contact Resources Exchange Links ebay