Background: Pulmonary vein isolation (PVI) is the cornerstone strategy for atrial fibrillation (AF) ablation. The dual muscular coronary sinus (CS) to left atrium (LA) connection, coupled with rate-dependent unidirectional block, is related with AF/ flutter induction.
Objective: To examine whether ablation of distal CS-LA connection at a first AF ablation reduces the atrial arrhythmia recurrences.
Methods: In the single center, prospective study (NCT03646643), 35 consecutive patients with drug refractory AF undergoing first time ablation during 2018 to 2019, were randomly assigned to standard ablation (PVI and non-PV trigger ablation), versus standard ablation plus elimination of distal CS-LA connection. The connection was targeted at the earliest activated LA focus during distal CS pacing (just above threshold to avoid direct LA capture) with a decapolar catheter placed with its proximal electrode at the ostium, adjacent to the septum. Change of LA activation to early activation of the LA septum or roof during distal CS pacing was the endpoint for elimination of connection.
Results: Thirty patients achieved 6 months follow-up (15 in each group). Demographic characteristics were similar (standard vs standard + connection elimination: 67±6 vs 65±8 years, p=0.4; 40% vs 67% male, p=0.1; 53% vs 60% paroxysmal AF, p=0.7; mean LVEF 57%±10% vs 56±13%, p=NS;). After a mean follow-up of 170±22 days, there were 7 recurrences in the standard group and 1 recurrence in the elimination group (47% vs 7%, HR 0.12, p=0.047).
Conclusion: Elimination of distal CS to LA connection reduced atrial arrhythmia recurrences compared to PVI and non-PV trigger ablation in patients referred for a first AF ablation.