Introduction: Atrial arrhythmias are a common and challenging complication of complex congenital heart disease with significant clinical implications. The limited data on ablation of atrial fibrillation (AF) within this cohort are guided by conventional mapping and pulmonary vein isolation (PVI). Rapid, charge density, non-contact mapping technology allows for specific, targeted lesion sets of great relevance to this population. We report the feasibility and initial experience of this approach within this complex cohort.
Methods: This pilot study recruited patients with high complexity congenital heart disease referred for ablation of persistent AF. All patients were referred with conventional indications for AF ablation following consensus in a congenital electrophysiology multidisciplinary team. Baseline demographics, anatomy, interventions, arrhythmias and previous ablations were recorded. Non-contact atrial mapping was undertaken in a single procedure with a charge density mapping system following cryo-balloon PVI. Conventional procedural metrics as well as acute success was recorded. All patients had clinical follow-up, including an electrocardiogram (ECG), at 3 and 6 months. Prolonged ECG monitoring or device interrogation was undertaken at 6 months and 1 year (if time point available).
Results: Four patients with persistent AF were referred and underwent ablation (Table 1). Mapping was undertaken via transvenous access and trans-septal or trans-baffle punctures. Limited or no pulmonary vein signals were noted in 3/4 patients; however, cryo-balloon isolation partially organised the rhythm in all cases. Non-contact mapping demonstrated variable substrate (Table 1) with ablation targets involving both the systemic venous and pulmonary venous atrium. Sinus rhythm was acutely restored in all patients with freedom from AF at 6 months. Recurrence of an organised arrhythmia was seen in two patients at 6 and 9 months with late recurrence of AF in a third. Two patients died from heart failure within 2 years.
Conclusions: Cryo-balloon PVI followed by non-contact mapping-guided ablation of persistent AF in complex congenital heart disease was feasible and achieved sinus rhythm in this pilot study. Successful ablation targets were highly variable. However, there is significant morbidity in this population related to the failing underlying circulations. These data support a larger study of this approach within this growing population. ❑