Background: Atriofascicular fibers are uncommon accessory pathways exhibiting decremental anterograde conduction, typically arising along the tricuspid annulus and inserting distally near the moderator band in the right ventricle. Information regarding these connections in young patients remains limited.
Aim: Describe clinical and electrophysiologic characteristics of atriofascicular fibers evaluated at our institution from 1988 through 2013.
Methods: Patients diagnosed with an atriofascicular fiber at electrophysiologic study (EPS) were identified using computerized data from departmental database. Demographics and comorbidities were recorded, as well as electroanatomic characteristics. If catheter ablation was attempted, acute and long-term outcomes were ascertained.
Results: Forty one consecutive patients were identified with a median age at diagnosis of 9 yrs (range, 0.5-17 yrs). Congenital heart defects were present in 13 pts (32%), usually in the form of Ebstein`s anomaly (8 pts). Additional tachycardia substrates were present in 13 pts, including conventional accessory pathways in 7 and AV node reentry in 6. All but 2 pts had inducible antidromic reentry at EPS, and 21 demonstrated spontaneous fiber automaticity. Radiofrequency catheter ablation was attempted in 30 patients, with an acute success rate of 97% and no acute complications. During a mean follow up of 7 yrs, recurrence was observed in 7 pts (23%, only one with congenital heart disease) who all underwent repeat ablation. Recurrence was still observed after the 2nd ablation attempt in 2 of these 7. With the exception of 1 pt who died secondary to complications of severe Ebstein`s anomaly, no other serious complications occurred during follow up.
Conclusions: Congenital heart defects (particularly Ebstein’s) and multiple arrhythmia substrates frequently accompany atriofascicular fibers in young patients. Acute ablation outcomes are optimistic, but the recurrence rate remains higher than conventional accessory pathways.
