Objective: Atriofascicular (Mahaim) pathways (MP) are a rare reason for supraventricular tachycardia in childhood. We analyzed results of RF ablation and further clinical course of patients with AV reentrant tachycardia due to MP.
Methods: Data from 18 consecutive pts. from 2 centers aged 9.1 - 19.6 (median 14.9) years, who underwent RF ablation of a MP between 1998-2008 (follow-up: median 14.1, range 0.2-50.6 months) were analyzed.
Results: MP was located at right lateral (9 pts.) or posterolateral (9 pts.) tricuspid annulus. Mapping was based on the finding of a specific Mahaim potential in 14/18 pts. and/or on intermittent catheter-induced mechanical conduction block in the MP in 9/18 pts. Acute ablation success rate was 100 %. Of the 18 patients with initially successful ablation, 4 pts. had arrhythmia recurrence and 3 of them were successfully re-ablated carrying a total long-term ablation success rate of 94 % (17/18 pts.). The remaining pat. is on antiarrhythmic medication. In 5/18 pts. additional arrhythmogenic substrates were found: WPW syndrome in 2 pts., concealed atrioventricular pathway in 1 pat. and AVNRT in 2 pts.. All of these substrates were successfully ablated. Mean fluoroscopy time was 22.4 (range 5.9 – 64.3) minutes. There was one minor procedure-related complication, no major complications were observed.
Conclusions: Mapping of MP may be hampered by frequent mechanical conduction block. Ablation therapy is effective and incidence of MP recovery approaches figures reported for conventional right free wall pathways. (Supported by Research Project No 00064203 of University Hospital Motol, Prague, Czech Republic).