COMPLETENESS OF LINEAR OR FRACTIONATED ELECTROGRAM ABLATION IN ADDITION TO PULMONARY VEIN ISOLATION ABLATION OUTCOME: A SUB-STUDY OF THE STAR AF II

Abstract

<h3>BACKGROUND</h3> The STAR AF II (Substrate and Trigger Ablation for Reduction of Atrial Fibrillation 2) was a multicenter, randomized trial which randomized patients to pulmonary vein isolation (PVI) alone, PVI plus complex fractionated electrograms (CFE), or PVI plus linear ablation (roof line and mitral line). The study failed to show any additional benefit of additional substrate ablation (CFE or lines) in addition to PVI. However, complete block of linear ablations or total elimination of CFE was not achieved in all patients in the adjuvant ablation arms and this could explain why these additive ablation strategies did not improve outcome. We sought to determine whether completeness of adjuvant linear or CFE ablation affected the outcome of these additive ablation strategies when combined with PVI. <h3>METHODS AND RESULTS</h3> In STAR AF II, 549 patients were randomized 1:4:4 to PVI alone, PVI plus lines, and PVI plus CFE. In this substudy, outcomes of patients with complete linear block and without complete linear block in the PVI + lines group and outcomes for patients with all CFE regions successfully ablated and without all of them ablated in the PVI + CFE are analysed. Of the 243 patients in the PVI plus lines group who received both mitral and roof lines, bidirectional block across both lines was achieved in 179 (74%) but was not achieved in 65 (26%). At 18 months follow-up, AF recurrence occurred in 107 of 179 patients (59.8%) with complete block conduction block across lines and in 40 of 64 patients (62.5%) without complete block (p=0.89) (Figure 1). Even after 2 procedures, AF recurred in 51.9% of patients with complete linear block and 46% of patients without complete block (p=0.09). Of the 207 patients in the PVI plus CFE group who actually underwent CFE ablation, 188 (91%) had elimination of all CFE sites while all CFE were not eliminated in 19 (9%). At 18 months follow-up, AF recurrence occurred in 117 of 188 patients (62.2%) with all the CFE ablated and in 11 of 19 patients (57.9%) without all CFE ablated (p=0.47) (Figure 1). After 2 procedures, AF recurrence occurred in 56.7% of patients with all CFE ablated and 68.0% of patients without all CFE ablated (p=0.29). <h3>CONCLUSION</h3> PVI combined with both linear and CFE ablation did not result in less AF recurrence compared to PVI alone even after more than one procedure regardless of how well empiric linear or CFE ablation is performed.