Spatial autocorrelation dimension as a potential determinant for the temporal persistence of human atrial and ventricular fibrillation

Background:Despite being central to atrial fibrillation (AF) and ventricular fibrillation (VF) mechanisms and therapy, the factors governing AF and VF termination are poorly understood. It has been noted that ratio of system size (L) and the two-point spatial correlation length (ξ2) are associated with time until termination in transient spatiotemporally chaotic systems, but the relationship between these characteristics and termination has not been systematically studied in human AF and VF.Objective:We aimed assess whether the time to cardiac fibrillation termination can be predicted using a novel estimator, the spatial autocorrelation dimension (Di), defined as the ratio ofLand ξ2, in human AF and VF.Methods:Diwas computed and compared in a multi-centre, multi-system study with data for sustained versus spontaneously terminating human AF/VF. VF data was collected during coronary-bypass surgery; and AF data during clinically indicated AF ablation. We analyzed: i) VF mapped using a 256-electrode epicardial sock (n=12pts); ii) AF mapped using a 64-electrode constellation basket-catheter (n=15pts); iii) AF mapped using a 16-electrode HD-grid catheter (n=42pts). To investigate temporal fibrillation persistence, the response of AF-episodes to flecainide (n=7pts) was also studied.Results:Spontaneously terminating fibrillation demonstrated a lowerDi(PDiwas also seen in paroxysmal compared to persistent AF (P=0.002). Post-flecainide,Didecreased over time (PDiwas also associated with longer-lasting episodes of AF/VF (R2>0.90, PConclusion:Dipredicts the temporal persistence of cardiac fibrillation. This finding provides potentially important insights into a possible common pathway to termination and therapeutic approaches.