Syndrome of Wolf-Parkinson-White

Described in 1930 by Doctors Wolf, Parkinson and White, the syndrome of Wolf-Parkinson-White (WPW) is a Trouble secondary cardiac rhythm with a syndrome of electric pre-excitation ventricular.

Physiopathology

At the healthy individuals, the electric activity of the Cœur is initiated on the level of the sinusal Nœud (localized with the junction between the higher Vena cava and the right auricle). The wave of depolarization is then propagated towards the auriculo-ventricular Noeud (located at the low part of the right auricle), then towards the Ventricule S via the Faisceau of His.

The auriculo-ventricular node acts like a " barrier " , limiting the electric activity which reaches the Ventricule S. This function is essential because if the electrical signal generated on the level of the auricle S increases (as it during the auricular Fibrillation is the case or of the flutter), the auriculo-ventricular node will limit the electric activity which will be led to the Ventricule S.
For example, if the oil poppies are electrically activated with 300 beats per minute, approximately half of the electric impulses will be blocked by the auriculo-ventricular node; thus, the ventricles will be activated with approximately 150 beats per minute (thus giving a pulse of 150/minute).

Another important function of the auriculo-ventricular node is to be able to slow down the electric impulses. That is translated on the electrocardiogram by the space PR , which corresponds to time separating activation from the auricle S (wave P) and the activation of the Ventricule S (complex QRS).

The individuals presenting a syndrome of Wolf-Parkinson-White have a way of auriculo-ventricular conduction additional, called beam of Kent . This additional way corresponds to an electric communication abnormal between the auricle S and the Ventricule S.
Cette way does not share the properties of the auriculo-ventricular node quoted above. The Ventricule S are not able, when the electric impulses increase, to contract in a uniform way also quickly and thus go fibriller.

This additional way goes, in certain circumstances, " court-circuiter" the auriculo-ventricular node, outcome with a premature depolarization of the Ventricle.
In the event of auricular Fibrillation, of use of Digitalique S, inhibiting calcic, conduction in the auriculo-ventricular node is slowed down, thus directing the nerve impulses towards this additional way. This exposes at the risk of fast and badly tolerated tachyarythmy which can " dégénérer" in ventricular Fibrillation.

Other types of additional beams can exist:

direct connection between the auricle and the Beam of His (interval short PR, without waves delta): Syndrome of Lown-Ganong-Levine,
beam connecting the Beam of His (or one of its branches) directly with the Myocardium.

Epidemiology

Its Incidence is difficult to specify because a certain number of syndromes of Wolf-Parkinson-White are not diagnosed.
Les men is more frequently reached than the women. This syndrome can touch all the age brackets but more frequently meets in the child and the young adult.

Diagnosis

Private clinic

The majority of the subjects remain asymptomatic throughout their life.
Dans the contrary case, it can appear by crises of paroxystic Tachycardie of the type Bouveret. It can also involve syncope S or a Sudden death by auricular Fibrillation complicated of ventricular Fibrillation.

Electrocardiogram

When the rate/rhythm is sinusal (normal cardiac rhythm), one finds an aspect characteristic of this Syndrome: the waves delta : the slope at the beginning of the rising branch of the wave R is not as stiff as normally. After some hundredths of second, the slope becomes again normal. This wave delta , which is added again before and during the initial phase of the wave R, involves a shortening of the interval PR and a lengthening of the duration of the complex QRS (widening of complexes QRS), as well as disorders of the repolarization.

This characteristic aspect is due to the fact that at the subjects reached of a syndrome of Wolf-Parkinson-White, the electric activity initiated on the level of the sinusal Nœud is propagated not only via the auriculo-ventricular Nœud but jointly by the additional way. This second way not having the properties of the auriculo-ventricular node (see Physiopathology ), the electric impulse activates the Ventricule S in first by the additional way, and immediately afterwards by the normal way: what explains space PR runs and the wave delta.

The syndrome of Wolf-Parkinson-White can also be noted on the electrocardiographic layout of a subject in cardiac arrest. In this case, the layout shows a Tachycardie with widened complexes QRS and forms variable.

Causes

The cause is unknown in approximately 95% of the cases.
Il is described family forms.
Le syndrome of Wolf-Parkinson-White is sometimes associated with the optical Neuropathie of Leber, Genetic disease related to an attack of DNA mitochondrial.

Assumption of responsibility

Evaluation of the risk of sudden death

The decision to cover or not a subject presenting a syndrome of Wolf-Parkinson-White is made after having evaluated for each individual the risk of Sudden death.
Un good interrogation must be carried out in the search of unexplained episodes of Syncope or Palpitation S, then being able to be due to early episodes of Tachycardie in connection with the additional way.

The people presenting a syndrome of Wolf-Parkinson-White and whose waves delta disappear with the increase from the cardiac rhythm (for example with the effort) are at the weak risk of sudden death. The disappearance of the wave delta shows that the additional way cannot lead electric impulses to a fast rate/rhythm.

It is considered that there exists an high-risk of sudden death when the refractory period of the additional way is short, when there exist several additional ways, in the event of septal localization of the additional way.
Les individuals presenting any of these characteristics must be treated.

Treatment

The subjects presenting a badly tolerated tachyarythmy must profit from a Défibrillation. When their state is stable, a medicamentous treatment Antiarythmique can then be proposed.

The radical treatment of the syndrome of Wolf-Parkinson-White includes/understands the destruction of the additional way by radio frequency. Ablation by radio frequency is not proposed on all the subjects presenting a syndrome of Wolf-Parkinson-White because of the inherent risks to the technique itself.
Si ablation by radio frequency of the additional way is carried out successfully, the subject generally is regarded as cured.

References

Brembilla-Perrot B. Ghawi R. electrophysiological Dechaux J.P. Characteristic of the asymptomatic syndromes of Wolf-Parkinson-White. Arch Badly Vaiss Heart Nov. 1991 ; 84 (11): 1549-1554. 8472715
Nikoskelainen E.K. Savontaus M.L. Huoponen K. Antila K. Hartiala J. Pre-excitation syndrome in Leber' S hereditary optic neuropathy. Lancet 1994 Seven ; 344 (8926): 857-8
Mashima Y. Kigasawa K. Hasegawa H. Tani Mr. Oguchi Y. High incidence off pre-excitation syndrome in Japanese families with Leber' S hereditary optic neuropathy. Clinical Genetics 1996 ; 50 (6): 535-537. 9147893.
Rosner M.H. Brady W.J. Kefer M.P. Martin M.L. Patient Electrocardiography in with the Wolf-Parkinson-White syndrome: initial diagnosis and therapeutic resulting. American Newspaper off Emergency Medicine 1999 ; 17 (7): 705-714. 10597097.
Gollob M.H. Green M.S. Tang A.S. Gollob T. Karibe A. Ali Hassan A.S. Ahmad F. Lozado R. Shah G. Fananapazir L. Bachinski L.L. Roberts R. Hassan A.S. Identification off has responsible embarrassment for family Wolf-Parkinson-White syndrome. NR Engl J Med 2001 ; 344: 1823-1831.
Pappone C. Santinelli V. Manguso F. Augello G. Santinelli O. Vicedomini G. Gulletta S. Mazzone P. Tortoriello V. Pappone A. Dicandia C. Rosanio S. has randomized patient studies off prophylactic catheter ablation in asymptomatic with the Wolf-Parkinson-White syndrome. New England Journal off Medicine 2003 ; 349 (19): 1803-1811. 14602878.
Milliez P. Slama R. Syndrome of Wolf-Parkinson-White. Rev Prat Oct. 2004 ; 54 (16): 1747-1753. 15630877
Triedman J. Perry J. Van Hare G. Risk stratification for prophylactic ablation in asymptomatic Wolf-Parkinson-White syndrome. NR Engl J Med 2005 Jan ; 352 (1): 92-93. 15635121
Scheinman M.M. History off Wolf-Parkinson-White syndrome. Pacing Electrophysiol Covering joint 2005 Feb ; 28 (2): 152-156. 15679646

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