Title of Trial
A Randomized Study of Prophylactic Catheter Ablation in Asymptomatic Patients with the Wolf-Parkinson-White Syndrome
Date and Citation of Primary Publication(s) or References
Nov. 6, 2003. NEJM 349:1803-1811
Purpose of the Trial
This study evaluated the approach of catheter ablation in patients with asymptomatic WPW who had reproducibly inducible arrhythmias in the EP lab and were 35 years old or younger.
Study Categories
Ablation
Patient Population
Patients with asymptomatic WPW, 35 years old or younger.
Inclusion Criteria
- Ventricular preexcitation documented by 12 lead ECG
- Absence of arrhythmia related symptoms
Exclusion Criteria
- Participation in other research protocols
- Age less than 13 years
- Pregnancy or concomitant medical conditions
Study Design
Patients were selected from 224 asymptomatic patients with ventricular preexcitation. Electrophysiologic studies were performed on each patient. Patients were classified as high risk (n=76) if arrhythmias (atrial fibrillation or AVRT) were reproducibly induced. These 76 patients were then randomly assigned to ablation therapy vs. control. All patients including those not classified as high risk were evaluated once a year.
Endpoint
The occurrence of symptomatic arrhythmic events including supraventricular tachycardia, atrial fibrillation and ventricular fibrillation.
Baseline Characteristics
| | High risk Patients
(Ablation group n=37) | High risk Patients
(Control group n=35) |
| Age | 23 | 22 |
| Gender (% Male) | 53 | 47 |
| Structural heart disease | 0 | 0 |
| Inducibility (%) | 38 | 37 |
| Nonsustained AF | | |
| AVRT | 41 | 40 |
| AVRT triggering AF | 22 | 23 |
| Anterograde refractory period of accessory pathway (msec) | 240 | 240 |
| Anterograde refractory period of accessory pathway after isoproterenol (msec) | 200 | 200 |
| Shortest preexcited RR interval during atrial fibrillation (msec) | 250 | 240 |
| Median follow-up time (months) | 27 | 25 |
Results
The rate of arrhythmic events in patients classified as high risk who did not undergo ablation was 77% over a five year period. In patients classified as high risk who underwent ablation this risk was 7% over a five year period (p<0.001, RR 0.08, 95% CI 0.02-0.33). Thus, there was a 92% risk reduction for arrhythmic events in high risk patients who underwent ablation. After adjustment for covariates, the relative risk for patients who had an ablation was 0.016 (p<0.001, 95% CI 0.002-0.104).
Of the remaining 148 low risk patients, symptoms of supraventricular tachycardia developed in 6 patients.
Trial Status: Completed
Review written by Amin Al-Ahmad, MD 
