OpenEP: A Cross-Platform Electroanatomic Mapping Data Format and Analysis Platform for Electrophysiology Research

Figures

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  FIGURE 1. OpenEP Overview. The core components of OpenEP are the data parsing modules (used to parse data from proprietary clinical system formats) and the data analytics modules (used to access and analyze the data stored in OpenEP format).

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  FIGURE 2. (A) Import time was proportional to the number of mapping points in the clinical dataset. (B) Storage space required for electroanatomic mapping data was three orders of magnitude smaller than the uncompressed Carto data and two orders of magnitude less than the compressed Carto data.

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  FIGURE 3. Geometric measurements compared between the original electroanatomic mapping system and OpenEP. (A) Number of mapping points present in the original Carto map and subsequently identified by OpenEP, using getNumPts(userdata). (B) Chamber volume measured by Carto and OopenEP, using getVolume(userdata). (C) Chamber area measured by Carto and OpenEP, using getArea(usredata, 'method', 'nofill'). (D) Chamber area measured by Carto and OpenEP, using getArea(usredata, 'method', 'fill').

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  FIGURE 4. Miscellaneous OpenEP functions. (A) Identification of anatomical structures using the OpenEP command: getAnatomicalStructures(userdata, 'plot', true). (B) Identification of point status for points referenced in userdata using [inoutpts, meshrefpts] = pointStatus(userdata, 'plot', true).

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  FIGURE 5. Local activation time mapping. (A) Activation maps exported from the Carto electroanatomic mapping platform. (B) Activation map created by OpenEP using the Carto electroanatomic mapping data. OpenEP command: drawMap(userdata, 'type', 'act', 'orientation', 'ap'). (C) Activation map created by OpenEP using the Carto electrogram data. OpenEP command: interpData = generateInterpData(userdata, 'lat-map'); drawMap(userdata, 'type', 'act', 'orientation', 'ap', 'data', interpData). AP, antero-posterior; PA, postero-anterior; LAT, local activation time.

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  FIGURE 6. Quantification of OpenEP local activation time maps. (A) Cross correlation matrix comparing Carto-defined total activation time with the six total activation time metrics available in OpenEP. (B) Point-by-point comparison of Carto-defined local activation time and OpenEP-defined local activation time maps.

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  FIGURE 7. Identification of the site of earliest activation. (A) Example activation map showing the site of earliest activation, defined as the earliest local activation time recorded by Carto shown in red, and the site of earliest activation using the OpenEP percentile method shown in blue. (B) Relationship between Carto earliest activation sites and OpenEP earliest activation sites for all 40 cases. The Carto-defined earliest activation sites are shown with red spheres and the OpenEP-defined earliest activation sites are shown with blue spheres. The connecting lines indicate the pairing of data points on a case-by-case basis. LAO, left anterior oblique; LAT, local activation time.

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  FIGURE 8. Conduction velocity measurement using OpenEP software. (A) Conduction velocity maps of two cases in anterior-posterior orientation (left) and postero-anterior orientation (right). Maps created using the OpenEP function: drawMap(userdata, 'type', 'cv', 'coloraxis', [0 2], 'orientation', 'pa'). (B) Conduction velocity histograms corresponding to the maps in panel A; created using the OpenEP function call: cvHistogram(userdata). CV, conduction velocity; AP, antero-posterior; PA, postero-anterior.

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  FIGURE 9. Bipolar voltage mapping. (A) Voltage maps created using Carto, with a voltage threshold of 0.5 mV. (B) Voltage maps created using OpenEP with a voltage threshold range of 0.4–0.6 mV applied to the voltage mapping data exported by Carto. OpenEP command: drawMap(userdata, 'type', 'bip', 'coloraxis', [0.4 0.6], 'orientation', 'pa', 'colorfillthreshold', 10); (C) Voltage maps created using OpenEP with a voltage threshold range of 0.45–0.55 mV, interpolated from the raw electrogram data at every mapping point and with a color fill threshold of 10 mm. OpenEP command: interpBip = generateInterpData(userdata, 'bip-map'); drawMap(userdata, 'data', interpBip, 'type', 'bip', 'coloraxis', [0.4 0.6], 'orientation', 'pa'). AP, antero-posterior; PA, postero-anterior; Bi, bipolar voltage.

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  FIGURE 10. Analysis of Carto and OpenEP voltage mapping data. (A) Assessment of mean chamber voltage using Carto and OpenEP. (B) Assessment of low voltage area using Carto and OpenEP. The OpenEP commands: getMeanVoltage(userdata, 'method', 'map'); getMeanVoltage(userdata, 'method', 'egm'); getLowVoltageArea(userdata, 'method', 'map'); and getLowVoltageArea(userdata, 'method', 'egm') were used to create the data for these figures.

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  FIGURE 11. Voltage histogram analysis. (A) Voltage histogram analysis performed using bipolar voltages exported from the clinical mapping system. OpenEP command: voltageHistogramAnalysis(userdata, 'plot', true, 'method', 'map'). (B) Voltage histogram analysis performed using bipolar voltages re-interpolated from the exported electrogram voltage annotations using the OpenEP command voltageHistogramAnalysis (userdata, 'plot', true, 'method', 'egm'). Inset in lower panel shows the comparison in areas between the two methods.

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  FIGURE 12. Display of electrogram data using OpenEP. (A) Reference, bipolar and unipolar electrogram data at five selected sites on the posterior wall of a left atrium. (B) Corresponding electrograms extracted and plotted using OpenEP. Blue – bipolar electrogram; green – paired unipolar electrograms; red – reference coronary sinus electrogram. Red dots indicate the activation time annotations extracted from the clinical mapping platform. OpenEP function example: plotOpenEPEgms[userdata, 'iegm', getIndexFromCartoPointNumber(userdata,1042)]. LAT, local activation time; CS, coronary sinus; Pent, PentaRay; Uni, Unipole; Bip, Bipole.