BACKGROUND: Functional changes of the accessory AV pathways and dual AV node pathways are very important for patients with Wolff-Parkinson-White syndrome or AV node reentrant tachycardia who refuse to receive long-term medication or radiofrequency catheter ablation. However, no studies of serial clinical and electrophysiological characteristics in these patients have been performed. METHODS AND RESULTS: One hundred thirteen patients with Wolff-Parkinson-White syndrome or AV node reentrant tachycardia were included in this study. The first and second follow-up electrophysiological studies were performed in years 5 and 10 after the baseline study, respectively. Conduction properties of the accessory pathways became poor over time. After a mean follow-up period of 9 +/- 1 years, antegrade ventricular preexcitation and retrograde accessory pathway conduction disappeared in 22.5% and 7.8% (P < .01), respectively; dual AV node pathway physiology persisted and retrograde fast pathway disappeared in 10.8% of the patients. Baseline conduction properties of the antegrade and retrograde accessory pathways and the retrograde fast pathway independently predicted late loss of conduction. Spontaneous disappearance of the original tachyarrhythmias occurred in 10.3% of all patients, and newly developed tachyarrhythmias in 15.2%. The incidence (38.5%) of newly developed atrial fibrillation was significantly higher in patients with manifest accessory pathways. Furthermore, symptom scores and attack frequency increased significantly over time in the patients with accessory pathways and AV node reentrant tachycardia. CONCLUSIONS: Disappearance of the original tachycardia and changing patterns of tachycardia, also with an increase in symptom scores and attack frequency, suggested that a detailed evaluation of these events is important and early intervention with radiofrequency ablation would be helpful.
BACKGROUND: Functional changes of the accessory AV pathways and dual AV node pathways are very important for patients with Wolff-Parkinson-White syndrome or AV node reentrant tachycardia who refuse to receive long-term medication or radiofrequency catheter ablation. However, no studies of serial clinical and electrophysiological characteristics in these patients have been performed. METHODS AND RESULTS: One hundred thirteen patients with Wolff-Parkinson-White syndrome or AV node reentrant tachycardia were included in this study. The first and second follow-up electrophysiological studies were performed in years 5 and 10 after the baseline study, respectively. Conduction properties of the accessory pathways became poor over time. After a mean follow-up period of 9 +/- 1 years, antegrade ventricular preexcitation and retrograde accessory pathway conduction disappeared in 22.5% and 7.8% (P < .01), respectively; dual AV node pathway physiology persisted and retrograde fast pathway disappeared in 10.8% of the patients. Baseline conduction properties of the antegrade and retrograde accessory pathways and the retrograde fast pathway independently predicted late loss of conduction. Spontaneous disappearance of the original tachyarrhythmias occurred in 10.3% of all patients, and newly developed tachyarrhythmias in 15.2%. The incidence (38.5%) of newly developed atrial fibrillation was significantly higher in patients with manifest accessory pathways. Furthermore, symptom scores and attack frequency increased significantly over time in the patients with accessory pathways and AV node reentrant tachycardia. CONCLUSIONS: Disappearance of the original tachycardia and changing patterns of tachycardia, also with an increase in symptom scores and attack frequency, suggested that a detailed evaluation of these events is important and early intervention with radiofrequency ablation would be helpful.