Transbaffle mapping and ablation for atrial tachycardias after mustard, senning, or Fontan operations

Background: In Fontan and atrial switch patients, transcatheter ablation is limited by difficult access to the pulmonary venous atrium. In recent years, transbaffle access (TBA) has been described, but limited data document its safety and utility.

Methods and results: All ablative electrophysiological study cases of this population performed between January 2006 and December 2010 at Boston Children's Hospital were reviewed. Pre-case and follow-up clinical characteristics were documented. Adverse events were classified by severity and attributability to the intervention. We included 118 cases performed in 90 patients. TBA was attempted in 74 cases and was successful in 96%: in 20 via baffle leak or fenestration and in 51 (94%) of 54 using standard or radiofrequency transseptal techniques. There were 10 procedures with adverse events ranked as moderate or more severe. The event rate was similar in both groups (TBA 8% versus non-TBA 9%, P = 1), and no events were directly attributable to TBA. There was a trend to higher proportion of cases having a > 5-point drop in saturations from baseline in the TBA group versus the non-TBA group in Fontan cases (15% vs 0%, P = 0.14). When cases with follow-up > 90 and > 365 days were analyzed, the median initial arrhythmia score of 5 significantly changed--3 points in both time periods (P ≤ 0.001).

Conclusions: TBA is feasible in this population; its use was not associated with a higher incidence of adverse events; and changes in clinical scores support its efficacy. Desaturation observed in some patients is of uncertain significance but warrants postablation monitoring and prospective study.