Impact of the individual relationship between focal or rotational regions of interest and atrial cardiomyopathy in patients with chronic forms of atrial fibrillation

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: The mechanisms for the initiation and perpetuation of atrial fibrillation (AF) are still not completely understood. The CARTOFINDER module represents a novel approach for the visualisation of repetitive focal and rotational activations in patients with AF. PURPOSE: The aim of this prospective observational study was to evaluate the potential relationship between findings from CARTOFINDER mapping and individual atrial arrhythmia substrates. Beyond that, the impact of atrial fibrosis on patients’ outcome was analysed. METHODS: A total of 20 consecutive patients (69 ± 9 years, 55 % male) underwent ablation for persistent AF (PERS) applying a 3D-mapping system with the integrated CARTOFINDER module. Regions of interest (ROIs) were identified before ablation. The individual amount and distribution of atrial fibrosis in the left atrium (LA) based on anatomical segments was determined by LGE CMR prior to the ablation procedure. 3, 6 and 12 month-follow-up data were assessed. RESULTS: In all patients, ablation procedures were performed successfully (n=20, 100%). LA mapping time was 09.30 ± 03.53 min, mean ablation duration was 26.40 ± 07.51 mi, mean fluoroscopy time amounted to 6.66 ± 1.85 min. Consistent with Utah classes II-III, LGE-CMR revealed an intermediate degree of 21.41 ± 6.16% LA fibrosis. Focal and rotational ROIs were identified in all patients (mean no ROIs per Patient n = 416.45 ± 204.57). Univariate logistic regression calculation documented no consistent correlation between the percentage of LA fibrosis and the probability for the occurrence of ROIs (posterior: regression coefficient (b) =0.36, p-value (p) =0.24; anterior: b=-0.08, p=0.54; lateral: b=0.31, p=0,39; septal:b=-0.12; p=0.66; right PVs: b=0.34, p=0.27; left PVs: b=0.07, p=0.79; LAA: -0.91, p=0.11). Between the degree of atrial cardiomyopathy and the number of ROIs no association was observed (b=10.86, p=0.15). 12 months AF-free survival amounted to 70% (n=14). The degree of LA fibrosis showed no significant correlation with AF-free survival (logistic regression: posterior: b=0.33, p=0.12; anterior: b=-0.03, p=0.83; lateral: b=0.31, p=0,35; septal:b=-0.07; p=0.79; right PVs: b=0.81, p=0.15; left PVs: b=0.37, p=0.25; LAA: -0.16, p=0.54). CONCLUSIONS: This study reports on initial observations concerning the relationship between focal and rotational activations and atrial fibrosis in PERS AF. No evidence for a consistent correlation between the occurrence or number of ROIs and the degree of atrial arrhythmia substrates was revealed. Beyond that, the amount of LA fibrosis did not correlate with the 12 months AF-free survival rate. Larger studies are warranted to verify our first results.