From the Guidelines
Wolff-Parkinson-White (WPW) syndrome is a heart condition characterized by an extra electrical pathway between the atria and ventricles, causing rapid heartbeats (tachycardia) and potentially life-threatening complications, such as sudden cardiac death (SCD) 1.
Definition and Diagnosis
WPW syndrome is diagnosed when a patient's resting ECG shows ventricular pre-excitation, which is a delta wave, and the patient experiences arrhythmias 1. The extra electrical pathway, also known as an accessory pathway, can conduct in the anterograde direction, retrograde direction, or both, and can be associated with various supraventricular arrhythmias.
Risk Assessment and Treatment
The risk of SCD in patients with WPW syndrome is estimated to be around 0.15% to 0.24% over 10 years, with increased risk associated with a history of symptomatic tachycardia, multiple accessory pathways, and a shortest pre-excited R-R interval of <250 ms during atrial fibrillation (AF) 1.
- Treatment options for WPW syndrome include catheter ablation, which is the recommended definitive treatment for symptomatic patients, with success rates over 95% 1.
- Medications like flecainide, propafenone, or beta-blockers may be used to manage symptoms temporarily or for patients who cannot undergo ablation.
- Vagal maneuvers, such as bearing down as if having a bowel movement, may help slow the heart rate during acute episodes.
- Certain medications, such as digoxin, verapamil, and diltiazem, are contraindicated in emergency situations with unstable WPW, as they can worsen the condition 1.
Importance of Risk Stratification
Even asymptomatic patients with WPW syndrome should be evaluated for risk stratification, as some may benefit from prophylactic ablation if they have high-risk features, such as a short anterograde refractory period or multiple accessory pathways 1. Proper diagnosis through ECG, which typically shows a short PR interval and delta wave, is essential for identifying patients with WPW syndrome and determining the best course of treatment.
From the Research
Definition and Pathophysiology of Wolff-Parkinson-White (WPW) Syndrome
- WPW syndrome is a condition characterized by 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 2.
- The accessory pathways can cause atrioventricular reciprocating tachycardias (AVRTs) by allowing depolarization wavefronts to move anterograde through the AV node to the ventricles and returning retrograde to the atria along the AP 2.
- The presence of these accessory pathways can lead to rapid AVRT, which decreases ventricular filling time and cardiac output, resulting in symptoms 2.
Electrocardiographic Characteristics and Tachyarrhythmias Associated with WPW Syndrome
- The electrocardiographic characteristics of WPW syndrome include a short PR interval, presence of a delta wave, widened QRS complex, and ST-T wave changes 3.
- The most common tachyarrhythmias associated with WPW syndrome are orthodromic and antidromic reciprocating tachycardia and atrial fibrillation 3.
Treatment and Management of WPW Syndrome
- Treatment options for WPW syndrome include medications that prolong AP refractory periods, such as flecainide, propafenone, and amiodarone, which can prevent rapid AP anterograde conduction in atrial tachycardias 2.
- Catheter delivered radiofrequency (RF) energy is now applied intravascularly to ablate APs, and has become the initial nonpharmacological treatment of choice for WPW syndrome 2.
- Surgical ablation has become relegated to those cases where symptoms are intolerable and RF ablation is not feasible 2.