Wolff-Parkinson-White Syndrome

Wolff-Parkinson-White syndrome is the most common syndrome of premature ventricular excitation (it is observed in 0.1 - 0.3% of the population in the general population ^[4] ), which occurs when there is an additional Kent bundle. Most people do not have signs of heart disease. In men, the syndrome is detected more often than in women.

Kent's bundle is an abnormal bundle between the left / right atria and one of the ventricles. This bundle plays an important role in the pathogenesis of WPW syndrome. Faster pulse propagation through this additional conductive path leads to:

• 1) shortening of the interval P - R (P - Q);
• 2) earlier excitation of part of the ventricles - a wave occurs.

The biochemical background of the syndrome is a mutation in the CBS domain of the γ2 subunit of AMP-activated protein kinase (AMPK, AMP-activated protein kinase). The conservative (from prokaryotes to humans) CBS domain (~ 60 amino acids) is a site of allosteric regulation by AMP / ATP. ^[five]

In some patients, clinical manifestations may not be detected. The main manifestation of Wolff-Parkinson-White syndrome is arrhythmia . In more than 50% of cases, paroxysmal tachyarrhythmias occur: supraventricular reciprocal, atrial fibrillation, atrial flutter. Quite often, the syndrome occurs with heart diseases - Ebstein anomalies, hypertrophic cardiomyopathy , mitral valve prolapse .

WPW syndrome can occur secretly (latent syndrome is usually diagnosed using an electrophysiological study). This is due to the inability of additional conductive paths to conduct pulses in the antegrade direction. On the ECG during the sinus rhythm there are no signs of premature ventricular arousal. Hidden WPW syndrome is manifested by tachyarrhythmia , its detection is possible with ventricular electrical stimulation.

Explicit syndrome has a number of typical ECG signs:

• The short interval P - R (P - Q) is less than 0.12 s.
• Wave Δ. Its appearance is associated with a "confluent" contraction of the ventricles (first, the excitation of the ventricles through the additional conduction path, and then through the AB connection). When carried quickly through an AB connection, the wave Δ has a larger size. In the presence of AB-blockade, the ventricular complex consists entirely of the Δ wave, since the excitation to the ventricles is transmitted only through an additional path.
• The expansion of the QRS complex is more than 0.1 s due to the wave Δ.
• Tachyarrhythmias: orthodromic and antidromic supraventricular tachycardia , atrial fibrillation and flutter. Tachyarrhythmias usually occur after supraventricular extrasystoles.

Sometimes transient WPW syndrome is recorded on the ECG . This suggests that both paths of conducting the pulse alternately function — normal (AB path) and additional (Kent beam). In this case, normal complexes or deformed ones are visible.

Prevention and treatment of paroxysms of tachyarrhythmia

• To prevent attacks of tachycardia with WPW syndrome, you can use sotalol , disopyramides . It should be remembered that a number of antiarrhythmic drugs can increase the refractory period of the AB compound and improve the conduction of impulses through additional conduction pathways (slow calcium channel blockers, β-blockers, cardiac glycosides), and therefore their use in WPW syndrome is contraindicated.
• If atrial fibrillation syndrome occurs against the background, it is urgent to conduct electrical defibrillation . In the future, it is recommended to carry out the destruction ( radio-frequency catheter ablation ) of additional conduction paths.

Indications for the surgical treatment of Wolf-Parkinson-White syndrome

• The presence of frequent attacks of atrial fibrillation .
• Attacks of tachyarrhythmias with hemodynamic disorders (collapse).
• Preservation of attacks of tachyarrhythmia during antiarrhythmic therapy.
• Situations when long-term drug therapy is undesirable (young age, planned pregnancy).

Intracardiac radiofrequency ablation is the most effective (in 98% of cases) radical treatment for WPW syndrome.

WPW syndrome can be detected at any age, even in newborns. Any contributing heart disease occurring in violation of AV conduction can contribute to its manifestation. Permanent WPW syndrome, especially with attacks of arrhythmia , disrupts intracardiac hemodynamics, which leads to expansion of the heart chambers and a decrease in myocardial contractility .

The course of the disease depends on the presence, frequency and duration of the existence of tachyarrhythmias . Sudden coronary death in WPW syndrome occurs in 4% of cases, usually due to fatal arrhythmias ( atrial fibrillation , atrial flutter, ventricular tachycardia , ventricular fibrillation).

• http://wpw-syndrome.narod.ru/
• http://www.med74.ru/infoitem1326.html
• https://web.archive.org/web/20060524165135/http://www.cardiosite.ru/articles/article.asp?id=875