Abstract
Funding Acknowledgements
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG) through DO637/22-3 Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg through the Research Seed Capital (RiSC) program.
Introduction
Presence of left atrial (LA) fibrotic low voltage substrate (LVS) is associated with high risk for arrhythmia recurrences in patients undergoing pulmonary vein isolation (PVI) for atrial fibrillation (AF). PVI and additional ablation of LVS - as identified by mapping in sinus rhythm (SR) or AF - has been reported to improve SR maintenance rates, despite differences of the extent and distribution of LA-LVS in SR versus AF.
Aims
To study the relationship between SR and AF voltage maps, we sought to identify the optimal AF voltage threshold providing the highest concordance in the extent and distribution of LVS when comparing voltage maps in SR vs. AF.
Methods
Using the statistical shape modelling software Scalismo, the voltage information from the SR and AF maps (acquired prior to PVI) from 28 patients (66 ± 7 years, 46% male, 82% persistent AF) was projected onto a representative LA-geometry. Sensitivity and specificity of LVS identification were calculated for varying thresholds during AF and the correlation between the SR (threshold 0.5mV) and AF maps was assessed and areas of agreeing LVS classification (SR & AF) were identified for each patient. The data of all 28 patients were combined to a spatial histogram of agreement between SR and AF low voltage maps.
Results
The correlation between SR and AF maps was high across all patients, with agreement at 60-95% of all mapped sites (Figure A: each red triangle represents one patient and the respective agreement of LVS classification and substrate extent). The optimal AF threshold - to identify LA-LVS <0.5 mV in SR - was 0.29 mV (Q1-3: 0.20-0.37 mV) and was independent of the underlying extent of LVS during SR (Figure A: each blue asterisk represents one patient and the corresponding AF threshold and substrate extent). Agreement between LVS in AF vs. SR was high across most (>90) patients on the anterior LA, lateral LA and the left atrial appendage. Lower agreement (60% of patients) was observed in the posterior wall (Figure B).
Conclusions
SR and AF voltage maps reveal high spatial concordance in low voltage substrate at the anterior LA, lateral LA and LA appendage, however significant discordances in LVS are found in 40% of patients at the posterior LA. Further studies on an extended patient cohort should assess if regional voltage-thresholds would result in an improved substrate concordance between AF and SR substrate maps. Abstract Figure.
GW29-e0824 Correlation of left atrial low voltage and fractionation substrate between sinus rhythm and atrial fibrillation: high density mapping study in persistent Atrial Fibrillation
