Anterior mitral line in patients with persistent AF and anterior scar: a multicenter matched comparison. The MiLine Study

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: The benefit of an anterior mitral line (AML) in patients with persistent atrial fibrillation (AF) and anterior atrial scar undergoing ablation has never been investigated. OBJECTIVE: to evaluate the outcomes of AML on top of standard treatment, compared to standard treatment alone (no-AML), in this subset of patients. METHODS: Patients with persistent AF and anterior low voltage zone (LVZ) treated with AML in three Centers were retrospectively enrolled. These patients were matched in a 1:1 fashion with patients with persistent AF and anterior LVZ, who underwent conventional ablation, in the same centers. Matching parameters were: age, LVZ burden, and repeated ablation. Primary endpoint was AF/atrial tachycardia (AT) recurrence. RESULTS: 186 patients (66±9 years, 34% women) were selected and included into two matched groups. Bidirectional conduction block was achieved in 95% of AML. After a median follow-up of 2 years, AF/AT recurrence occurred in 29% of the patients in the AML-group, vs. 48% in the No-AML-group (log-Rank p=0.024) (Figure 1). At Cox-regression multivariate­-analysis left atrial volume (HR 1.03, p=0.006) and AML (HR 0.46, p=0.003) were significantly associated with the primary endpoint. At univariate logistic-regression, lower BMI, older age, extensive anterior LVZ and the position of the left atrial activation breakthrough away from the AML (Figure 2), were associated with first-pass AML block. CONCLUSION: In this retrospective matched analysis of patients with persistent AF and anterior scar, AML on top of standard treatment was associated with improved AF/AT-free survival compared with matched patients treated with standard treatment alone. [Figure: see text] [Figure: see text]