Wolff–Parkinson–White (WPW) Syndrome
Disease Description
Wolff–Parkinson–White (WPW) syndrome is a type of supraventricular tachycardia (SVT). It is a clinical and electrocardiographic syndrome characterized by specific ECG changes and episodes of sudden-onset rapid heart rhythm, with heart rates that may reach up to 250 beats per minute.
Causes of the Disease
WPW syndrome is caused by the presence of a congenital accessory electrical conduction pathway between the atria and the ventricles.
Under normal conditions, electrical impulses that control heart rhythm travel from the atria to the ventricles exclusively through the atrioventricular (AV) node, allowing the atria to complete contraction before ventricular contraction begins.
When an additional conduction pathway is present, the electrical impulse may, under certain conditions, travel backward from the ventricles to the atria through this accessory pathway, then again pass through the AV node to the ventricles. This creates a closed electrical circuit, causing rapid repetitive activation of the heart.
This mechanism is known as re-entry and plays a key role in the development of many cardiac arrhythmias.
Symptoms
Patients with WPW syndrome may experience sudden episodes of rapid palpitations lasting from several minutes to several hours (less commonly). These episodes often stop as abruptly as they begin.
Attacks may be accompanied by dizziness, shortness of breath, near-fainting sensations, or chest discomfort.
If you experience heart rhythm disturbances or any of these symptoms, prompt evaluation by a specialist is essential.
Diagnosis
Diagnosis of WPW syndrome is based on analysis of ECG recordings or 24-hour (Holter) ECG monitoring, which may reveal characteristic pre-excitation (“delta”) waves preceding the QRS complex.
However, specific ECG changes are not always present. In concealed WPW syndrome, ECG abnormalities may be absent, while in other cases ECG changes may exist without clinical arrhythmia episodes.
When symptoms are present, consultation with a cardiologist is mandatory. A definitive diagnosis is established using an invasive electrophysiological study (EPS).
This procedure is performed without general anesthesia under local anesthesia in a catheterization laboratory. Through a puncture in a femoral vein, specialized catheters are advanced into the heart to record intracardiac electrical signals. Controlled pacing maneuvers are used to determine the arrhythmia mechanism and confirm the diagnosis.
If EPS confirms WPW syndrome and identifies the arrhythmia mechanism, catheter ablation is usually performed during the same procedure.
Treatment
Medical therapy for WPW syndrome is generally ineffective.
The only radical and definitive treatment is radiofrequency catheter ablation (RFA) of the accessory conduction pathway.
Treatment Prognosis
Patients with WPW syndrome who experience recurrent tachycardia episodes are strong candidates for catheter ablation of the accessory pathway.
Approximately 50% of patients with WPW syndrome, including young individuals, may develop atrial fibrillation. Atrial fibrillation conducted through the accessory pathway is a potentially life-threatening condition, as it can degenerate into ventricular fibrillation and cause sudden cardiac death.