Sinus-rhythm conduction phenotyping using vector-flow mapping in first-time atrial fibrillation ablation: Associations with structural remodeling and thromboembolic risk.

BACKGROUND: Pulmonary vein isolation achieves success in 60%-80% of first ablation procedures. Sinus-rhythm vector-flow mapping (COHERENT module) may enable phenotype-guided ablation. OBJECTIVE: This study aimed to classify sinus-rhythm conduction phenotypes using COHERENT mapping and assess associations with atrial remodeling, recurrence, and thromboembolic risk. METHODS: We prospectively enrolled 80 consecutive patients (mean age 65.1 ± 12.5 years; 32.5% persistent atrial fibrillation [AF]) undergoing initial AF ablation with high-density sinus-rhythm mapping. 5 phenotypes were defined: normal flow, conduction delay, congested flow, disrupted flow, and Bachmann's bundle split (BBS). Patients were grouped into 8 mutually exclusive, collectively exhaustive phenotype-burden categories (normal, 4 single-phenotype groups, double, triple, quadruple). Outcomes were assessed by unadjusted logistic regression with normal as the reference; all 80 patients completed 24-month follow-up. RESULTS: Phenotype-burden categories showed gradients in structural and AF-related markers. Each 10 mL/m2 left atrial volume index increase was associated with higher odds of double (odds ratio [OR] 2.16), triple (3.02), and quadruple (3.46). 12 of 80 patients (15%) had 24-month recurrence; double showed the only nominally significant association (5 of 15 [33%]; OR 24.62; 95% confidence interval 1.16-521.53). BBS only and quadruple showed borderline odds for previous stroke/transient ischemic attack (each 2 of 7 [28.6%]; OR 21.36). CONCLUSION: Sinus-rhythm COHERENT mapping delineated distinct conduction phenotypes associated with progressive atrial structural remodeling. Phenotype burden defined a graded atrial cardiomyopathy continuum, with double showing the highest 24-month recurrence. BBS only and quadruple shared borderline thromboembolic signals via distinct mechanisms. These findings provide mechanistic insight into atrial cardiomyopathy and generate hypotheses for substrate-guided ablation and thromboembolic-risk assessment.