Comparison of voltage map-guided left atrial anterior wall ablation versus left lateral mitral isthmus ablation in patients with persistent atrial fibrillation.

BACKGROUND: Left lateral mitral isthmus (LLMI) ablation achieves a low percentage of bidirectional conduction block in atrial fibrillation (AF) ablation.

OBJECTIVE: The purpose of this study was to investigate whether linear ablation through the lowest voltage area on the left atrial anterior wall (LAAW) can lead to better clinical outcomes compared to LLMI ablation.

METHODS: We obtained high-density three-dimensional (3D) voltage mapping (CARTO) of the LA in 29 patients with persistent AF and determined the area of low voltage. In the multicenter prospective study, clinical outcomes of LAAW (n = 100) and LLMI ablations (n = 100) were compared in patients with persistent AF (79.4% male, 59.4 ± 10.6 years).

RESULTS: (1) The low-voltage area consistently existed on LAAW and had a correlation with the LA-aorta contact area (R = 0.921, P <.0001). Mean voltage of LAAW was significantly lower than that of LLMI (P <.0001). (2) The length of LAAW ablation (37.9 ± 3.4 mm vs 26.6 ± 3.2 mm, P <.0001) was longer, but achievement of bidirectional block was higher (68.0% vs 32.0%, P = .0001) than in LLMI ablation. Mean duration of LAAW and LLMI ablations was 19.3 ± 2.9 minutes and 18.2 ± 3.7 minutes, respectively (P = .086). (3) During follow-up of 23.3 ± 7.4 months, the recurrence rate of AF after LAAW ablation (26.0%) was significantly lower than that of LLMI ablation (41.0%, P = .021) after a single procedure.

CONCLUSION: The voltage map is useful for guiding linear ablation in persistent AF patients. LAAW is the most frequent low-voltage area around the mitral annulus, and linear ablation along LAAW results in a better clinical outcome with a higher rate of bidirectional conduction block compared to LLMI ablation.