Wolff-Parkinson-White syndrome (WPW syndrome) is a group of ailments related to a disorder of the heart. They are caused by the so-called the auxiliary pathway, or the wrong electrical pathway in the heart that causes the electrical impulses to propagate incorrectly. What exactly is it, what symptoms are characteristic of this syndrome and why can it be life-threatening?
Wolff-Parkinson-White syndromethat isWPW teambelongs to the so-called pre-excitation syndromes. What does it mean? In a he althy, normally functioning heart, the impulse to excite the muscle cells and cause them to contract synchronously is generated by the sinus node. Hence, it spreads through the atria, stimulating them to work. At the same time, this impulse goes to the atrioventricular node, through which it is transmitted to the ventricles. In the atrioventricular node, there is a minimal delay in impulse transmission (on the order of 0.1 seconds), which is necessary to properly synchronize the work of the atria and ventricles, and thus ensure optimal heart function.
In the case of pre-excitation syndrome, there is a so-called accessory pathway (most often the Kent's bundle) between the atria and the ventricles. The electrical impulse can therefore spread from the atria to the ventricles without delay, adversely affecting the efficiency of the heart. Moreover, the electrical activity of the ventricles may, via an additional or physiological pathway, cause the atria to reactivate at a rhythm different from that imposed by the sinus node. A further consequence of such atrial stimulation (by additional means through the electrical activity of the ventricles) may be the re-stimulation of the ventricles, this time by the physiological route, i.e. by the atrioventricular node or again by an additional one.
In the pre-excitation syndrome, there may be a situation where an electrical impulse circulates through the heart: atria - atrioventricular node - ventricles - accessory pathway - atria - and so on.
In this case, the main pulse generator, the sinus node, which regulates the speed of the heartbeat, loses this control and the heart rhythm becomes too fast. Another characteristic feature of WPW is tachyarrhythmia, i.e. too fast, irregular heartbeat caused by itabnormal retrograde conduction of impulse from the ventricles to the atria. Apart from the physiological course of the impulse, the following conduction pathways are possible in the WPW syndrome (the consequence of each of them is tachyarrhythmia):
- atria - atrioventricular node - ventricles - accessory pathway - atria
- atria - accessory pathway - ventricular - atrio-atrium node
The way the impulse runs can be distinguished on the basis of the ECG recording - the analysis of the QRS complex, the PQ interval, and it is the ECG that is the basic diagnostic tool. The most accurate, however, is the electrophysiological test, i.e. the observation of the course of electrical impulses through a receiver located in the heart.
WPW team symptoms
Symptoms appear early - that is, already in children and young people, because the existence of an auxiliary route (which causes WPW syndrome) is a congenital abnormality. The most common symptoms include:
- palpitations (comes on suddenly and suddenly stops)
- fits of fast heartbeat
- fainting
- the symptom is less frequent continuous fast heart rate.
Heart failure may be the consequence of untreated symptomatic WPW. Occasionally, the first symptom is ventricular fibrillation, which is one of the possible mechanisms of sudden cardiac arrest. This risk is particularly important in the case of people suffering from atrial fibrillation, when the accessory pathway conducts all impulses from the atria to the ventricles.
WPW team: treatment methods
Treatment of WPW syndrome is performed on an ad hoc basis, when it is necessary to stop an attack of rapid heartbeat (tachyartymia), and chronically, when the goal of treatment is to prevent or eliminate conduction by an additional route.
In the first case - in order to stop a tachyarrhythmia attack, the vagus nerve should be stimulated, the effect of which slows down the heartbeat, this can be achieved by massage of the carotid sinus, ice filling the face or provoking vomiting, pharmacological methods include beta drugs -blockers and calcium channel blockers.
The choice of a chronic treatment method depends on the intensity of symptoms and the patient's preferences. A conservative strategy can be used in the absence of symptoms and when there are single attacks of tachyarrhythmia, in such cases a "handy pill" is sometimes recommended, which is one dose of medication to take in the event of a seizure.
Chronic pharmacological treatment can be carried out with many drugs, including: beta-blockers, amiodarone, propafenone, unfortunately none of them completely eliminates the possibility of arrhythmia.The method that ensures complete recovery is invasive treatment - percutaneous ablation of the accessory pathway. The procedure is most often performed through the femoral vein and involves the destruction of the secondary pathway with radio frequency current. The risk of the procedure is small and the benefits are huge, taking into account the fact that an effective procedure prevents the risk of ventricular fibrillation, and also prevents the occurrence of tachyarrhythmias, thus relieving the patient from symptoms. Ablation may be the first-line treatment, even in asymptomatic patients, and certainly must be considered when pharmacological treatment is ineffective, or if the patient has had additive ventricular fibrillation, and if the patient has atrial fibrillation and the atrial impulse is conducted to the ventricles through the accessory pathway (without delay in the atrioventricular node). Ablation is also considered in the case of frequent attacks of tachyarrhythmias. Such a wide range of indications for ablation is due to the fact that it is a procedure that completely eliminates the risk of ventricular fibrillation associated with the accessory pathway.
The WPW syndrome is the result of an accessory pathway that interferes with the proper propagation of electrical impulses in the heart. It can be asymptomatic, cause only a feeling of faster, irregular heartbeat, sometimes the first manifestation is ventricular fibrillation. Pharmacological treatment is not fully effective, and complete recovery can only be achieved by ablation of the accessory pathway. It is important that the WPW team is detected and treated effectively, as its consequences can be life-threatening.