Wolff Parkinson's White (WPW) syndrome is a heart rhythm disorder caused by the abnormal presence of a bundle, the Kent bundle. WPW syndrome is rare: its incidence is low. The diagnosis is essentially based on the electrocardiogram. Treatment is medicinal or by endocavitary ablation in the most severe cases.
Definition: what is Wolff Parkinson White syndrome?
“The heart is an automatic pump which circulates the blood thanks to the contractions of the atria, then the ventriclesexplains Professor Nicolas Sadoul, cardiologist specializing in rhythmology at Nancy University Hospital. These contractions depend on sinus node, a cellular structure in the right atrium (or atrium), at the foot of the superior vena cava. The sinus node generates a electrical impulse, transmitted to the right atrium then to the left atrium. The atria contract almost at the same time and this contraction materializes by the P wave on the ECG (electrocardiogram)”.
Electrical excitation of the heart passes from the atria to the ventricles through a single location: the atrioventricular node. “It is the only electrical crossing point between these two structures of the heart. Excitation then travels along the bundle of His and its two branches to reach the two ventricles. This will lead to contraction of the ventricles which is manifested on the ECG by the QRS complex.,” specifies Professor N. Sadoul.
In the person who presents with syndrome de Wolff Parkinson Whiteelectrical excitation passes from the atria to the ventricles via the atrioventricular node, but also via the Kent beam.
Is it Bouveret's disease?
The Bouveret's disease is a type of junctional tachycardia (rapid heart rate). This is a condition of the conduction of cardiac impulse, characterized by tachycardia (accelerated heart rate), which begins and stops suddenly. Kent's bundle may be responsible for Bouveret's disease. In this case, it manifests itself by attacks of paroxysmal tachycardia.
Causes: Is Wolff Parkinson White Syndrome hereditary?
The syndrome de Wolff Parkinson White is a congenital condition. “The patient is born with Kent's bundle, he does not acquire it over time. Transmission is very rare.”
In the fetal stage, the heart is a tube which later develops into cavities. The bundle is a bit like an electric wire which should have gradually disappeared, but which ultimately remains in the organ.
The syndrome de Wolff Parkinson White can evolve over time, that is to say disappear or paradoxically, reveal itself and cause symptoms or not.
Symptoms: what are the most likely manifestations?
The syndrome de Wolff Parkinson White may be asymptomatic; it is sometimes discovered incidentally on the ECG. In cases where symptoms appear, rapid heart rhythms are the most common manifestations, including paroxysmal junctional tachycardias sometimes called Bouveret tachycardia and more rarely by a fibrillation atriale with rapid conduction to the ventricles.
Re-entry tachycardias
Normally, electrical excitation comes from the top and goes down. When part of the heart beats prematurely, the Kent bundle may not conduct between the atrium and the ventricle because it is in a refractory period.
However, when the electrical beam leaves its refractory periodit can conduct, but this time from bottom to top, creating an electrical circuit called a “re-entry circuit”, acting like a loop between the atrioventricular node and the bundle of Kent.
The patient may then present with tachycardia with a heart rate averaging 170 to 180 beats per minute. Tachycardia begins and stops abruptly. It can last from a few seconds to several hours. This type of tachycardia is not fatal, although sometimes very unpleasant, especially if it persists.
Atrial fibrillation
The atrial fibrillation with rapid ventricular conduction is one of the other rarer manifestations of Wolff Parkinson White syndrome. Atrial fibrillation is defined as anarchic electrical activity of the atria, with multiple electrical impulses and disorganized contractions of the atria.
Usually, the fibrillation atriale is a pathology occurring with age, the main complication of which is stroke. “It manifests itself by a sensation of irregular beats, but not necessarily very fastspecifies our cardiologist, because in normal subjects, the atrioventricular node slows down electrical impulses. On the other hand, in a patient with Kent beam, the electrical excitation sometimes passes very quickly between the atrium and the ventricle, causing a tachycardia which can sometimes be very rapid (250 beats per minute, or even more). Atrial fibrillation can then transform into ventricular fibrillation, one of the most serious forms of arrhythmia but which fortunately remains an exceptional complication..”
Risks: Does WPW syndrome strain the heart?
The heart is not designed to contract too quickly. If the heart rate is fast for a long time, especially in older people, the heart tires more quickly. “The formula for knowing their maximum heart rate is: 220 – the person's age.”For example, in a 70-year-old person, the average heart rate is 150 beats per minute.
During tachycardia, other symptoms may also appear, such as difficulty breathing, fatigue, sometimes chest pain and rarely fainting.
Diagnosis: how to know if you suffer from Wolff Parkinson White syndrome?
ECG or electrocardiogram
The diagnostic test for Wolff Parkinson White syndrome is l’ECG. The ECG allows the recording of the electrical activity of the heart, the muscular contraction of which generates an electrical signal. Electrodes are placed on the body to pick up this signal during heart contraction. The results of the ECG are presented in the form of successive signals defined by l'onde P (contraction of the auricles), the complexe QRS (contraction of the ventricles) and l’onde T (relaxation of the ventricles).
Delta waves on the ECG and presence of the Kent beam
The Kent beam can conduct electricity in the direction of descent (from the atrium towards the ventricle), but also in the direction of ascent. If the conduction takes place in the direction of descent, the QRS complex is modified on the diagnostic ECG, with the presence of a pattern called “where Delta”. If it is present on the resting ECG, we speak of “Kent patent” because it is visible on the ECG. If the Kent beam only conducts in the upward direction, there is no Delta wave. We then talk about “Hidden Kent” since it is not seen on the ECG.
Treatment: how to treat Wolff Parkinson White syndrome (endocavitary ablation)?
Medication treatment, including antiarrhythmic drugs, can be prescribed to the patient. Some forms of tachycardia can be stopped with treatment with maneuvers (vagal maneuvers in particular). The maneuvers are more effective if they are performed at the start of an arrhythmia. In the most severe cases, destruction of the additional conduit is possible; It is endocavitary ablation of the Kent bundles. “This intervention has existed since the end of the 1980s, the pioneers being the rhythmic cardiology team at Bordeaux University Hospital. The technique involves introducing a catheter into the heart endovascularly. The destruction of the beam is done by heat (radiofrequency) or by cold (cryo-ablation)”, concludes Professor N. Sadoul.