Local Electrical Dyssynchrony during Atrial Fibrillation: Theoretical Considerations and Initial Catheter Ablation Results

Figures

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  Fig 1. Definition of local electrical dyssynchrony. (a) An example of pairs of electrograms (first electrogram in black, second electrogram in gray) with low (left) and high (right) dyssynchrony level. At the top, original electrograms and below corresponding electrograms phases used to compute the dyssynchrony parameter. (b) Schematic of the circular catheter and calculation of dyssynchrony of a given data point ('D-2' in this example). (c) 3D map with color coded value of electrical dyssynchrony.

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  Fig 2. Correlation of electrical dyssynchrony and wave characteristics derived from high-density epicardial mapping. (a) An example of individual waves identification (each wave denoted in a different color) in mapped field. Electrical dyssynchrony was calculated using a subset of electrodes with positions indicated by gray circles resulting in comparable layout as in a case of the circular catheter. Relation of the mean dyssynchrony between given subset of electrodes and mean AF cycle length (b), the total number of waves detected during whole recording (c) and the mean size of detected waves (d). Each point in the plot represents a mean value from single 10 s recording. Each point in the graphs (b-c) denotes an estimate from a single recording.

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  Fig 3. Electrical dyssynchrony in the mathematical model. (a) A mathematical model of AF based on the presence of regions of dynamical instability leading to wave break (red regions). (b) Map of transmembrane voltage showing individual waves in red. (c) Bipolar electrograms measured at corners of the plaque demonstrating irregularity of morphology and temporal sequence of activations. (d) Dyssynchrony map reconstructed after simulation for 40 cycles. (e) Regions of high dyssynchrony (in red) became a target of virtual ablation (black regions). (f) The result of virtual ablation on the propagation pattern. (g) Ablation resulted in regularization as evidenced by electrical activity measured at corners of the plaque.

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  Fig 4. Example dyssynchrony maps with electrograms from areas of high and low dyssynchrony. (a) Dyssynchrony maps. Dyssynchrony level is color-coded with purple corresponding with the lack of dyssynchrony (regular local pattern of activity) and red corresponding to 90% of the maximum value of dyssynchrony in given map. Red areas became the targets of ablation. (b) Percentage of the assigned area taken by top 10% of dyssynchrony per patient. Distribution of all dyssynchrony values at all collected all data points (c) (bin size of 0.05).

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  Fig 5. Correlation of dyssynchrony and electrogram amplitude and fractionation. An example of low voltage electrogram and fractionated electrogram having a low degree of dyssynchrony (0.46 for full 8 s segment). (a) Locations of the points on the LA geometry. (b) and (d) 2 s fragments of electrograms. (c) and (e) Phases corresponding to both electrograms. (f) Superposition of the phases of both electrograms showing a high degree of overlap denoting low dyssynchrony. (g) The relationship between dyssynchrony and electrogram amplitude for all data points. (g) The relationship between dyssynchrony and electrogram fractionation for all data points (N = 2986).

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  Fig 6. Temporal stability of dyssynchrony measure. (a) Example maps of local dyssynchrony in first and last 4 s of recorded segment. (b) Correlation between local dyssynchrony in first and last 4 s of recorded segment (all data points). (c) The dependency of mean (c) and standard deviation (d) of dyssynchrony for different lengths of the electrogram used in the analysis.