From the Guidelines
Wolff-Parkinson-White (WPW) syndrome is a congenital heart condition characterized by an abnormal electrical pathway in the heart called an accessory pathway, which can lead to episodes of rapid heartbeat (tachycardia) and potentially life-threatening arrhythmias. This condition is typically identified by a distinctive ECG pattern showing a short PR interval and a delta wave 1. People with WPW syndrome may experience symptoms such as palpitations, dizziness, shortness of breath, and occasionally fainting, though some individuals remain asymptomatic.
Key Characteristics and Treatment Options
- The accessory pathway in WPW syndrome allows electrical signals to bypass the normal route and create a short circuit, leading to rapid heartbeat 1.
- Treatment options include medication, such as adenosine, beta-blockers, or calcium channel blockers to control acute episodes 1.
- Long-term management often involves catheter ablation, a procedure that destroys the abnormal pathway with success rates exceeding 95% 1.
- According to the 2006 guidelines, catheter ablation of the accessory pathway is recommended in symptomatic patients with AF who have WPW syndrome, particularly those with syncope due to rapid heart rate or those with a short bypass tract refractory period 1.
Importance of Proper Management
The condition affects about 1-3 per 1,000 people and can occur at any age, though symptoms frequently first appear in young adults 1. While most people with WPW syndrome lead normal lives, untreated severe cases can rarely lead to dangerous arrhythmias, making proper diagnosis and management important for those experiencing symptoms 1. Immediate direct-current cardioversion is recommended to prevent ventricular fibrillation in patients with a short anterograde bypass tract refractory period in whom AF occurs with a rapid ventricular response associated with hemodynamic instability 1.
From the Research
Definition and Pathophysiology of Wolff-Parkinson-White (WPW) Syndrome
- WPW syndrome is a disorder characterized by the presence of at least one accessory pathway (AP) that can predispose people to atrial/ventricular tachyarrhythmias and even sudden cardiac death 2.
- The syndrome results from the congenital presence of impulse-conducting fascicles, known as accessory pathways (APs) or bypass tracts, which connect atria and ventricles across the annulus fibrosis and are capable of preexciting portions of the ventricular myocardium 3.
- Ventricular myocardium is preexcited by use of an alternate conduction pathway or accessory pathway, bypassing the atrioventricular (AV) node 4, 5.
Electrocardiographic Characteristics
- Electrocardiographic characteristics of WPW syndrome show a short PR interval, presence of a delta wave, widened QRS complex, and ST-T wave changes 4, 6.
- The definition of WPW relies on the following electrocardiographic features: a PR interval less than 0.12 seconds, a slurring of the initial segment of the QRS complex (delta wave), a QRS complex widening with a total duration greater than 0.12 seconds, and secondary repolarization changes reflected in ST segment-T wave changes 6.
Associated Tachyarrhythmias and Risks
- The most common tachyarrhythmias associated with WPW syndrome are orthodromic and antidromic reciprocating tachycardia and atrial fibrillation 4.
- Patients with WPW syndrome are at risk of sudden death when a rapid ventricular response occurs during atrial fibrillation due to conduction through the accessory pathway 5.
- WPW syndrome can cause disabling symptoms and, in extreme cases, sudden cardiac death 6.
Management and Treatment
- Management of WPW syndrome may be quite challenging and can vary from only acknowledging the presence of the accessory pathway to pharmacological treatment or radiofrequency ablation 2.
- Short-term therapy includes vagal maneuvers, atrioventricular nodal blocking agents, or direct current cardioversion, while long-term therapy includes antiarrhythmic therapy, and surgical or catheter ablation 4.
- Radiofrequency catheter ablation is now applied intravascularly to ablate APs and has become the initial nonpharmacological treatment of choice for WPW syndrome 3.