ECG Simulation NCRR Overview Technology for the ECG Simulation project CardioWave BioPSE project background Tools developed to date Tools for the next phase

ECG Simulation NCRR CardioWave BioPSE Original Project Specification CardioWave software provides cardiac activation modeling: runs in parallel on a distributed memory machine. Interface with SCIRun, for SCIRun's modeling and visualization capabilities. Application steps: ­build a model based on DTI heart data ­visualize the fibers ­modify the model (e.g. ischemia) ­simulate activation [CardioWave] ­visualize the results (Vi, Ve, activation time) ­embed heart in an FEM torso model ­simulate volume conduction over time steps ­visualize torso surface potential maps and ECGs

ECG Simulation NCRR CardioWave BioPSE (2)

ECG Simulation NCRR CardioWave BioPSE (3) Required Technologies Modeling tools: ­region selection ­Morphological operators (flood fill, erosion/dilation) ­Teem's tensor utilities (eigen-decomposition) Simulation tools ­integrate Duke's "Vulcan" FVM code Visualization / Analysis tools ­spinning fibers ­time-dependent visualization ­synchronized viewers Infrastructure tools ­data import / export ­direct MATLAB file i/o ­sockets (control, data passing) ­annotations ­subnets ­data bundles

ECG Simulation NCRR CardioWave BioPSE (4) Demonstration of the Latest Technical Developments and Direction…

ECG Simulation NCRR Modeling Propagation At Tissue Level Using Scirun And Cardiowave Jeroen Stinstra Shibaji Shome Craig Henriquez Rob MacLeod Dave Weinstein

ECG Simulation NCRR Propagation of depolarization cell membrane depolarized state "resting" state  What is the role of the gap-junctions in propagation ?  What is the role of the membrane capacitance ?  What is the role of the distribution of the interstitial space ? Currents flow through the intra-cellular space and loop back through the extracellular space extracellular space intracellular space gap-junctions "Micro" domain model of propagation

ECG Simulation NCRR "micro" domain simulation New CardioWave/NeuroWave modules for microscopic simulations Geometric modeling of cardiac tissue at a microscopic dimension in matlab Visualization engine: SCIRun 3D graphs/ volume rendering SCIRun CardioWave Package: to control them all Simulation pieces

ECG Simulation NCRR SCIRun: running on local machine with good graphics hardware controlling the CardioWave Simulation and displaying all intermediate results cluster (super computer) Socket connection over the internet 1. Being able to log in and out of the simulation 2. Change update frequency depending on bandwidth 3. Being able to specify which part of the simulation you want to monitor CardioWave Simulation Separation pthread vs. MPI world, Separation of C and C++ code Separation of hardware requirements Remote computing

ECG Simulation NCRR Dataflowscheme: Input of scientific data Preprocessing of the data Run simulation Visualization of results MATLAB files Large simulation files (up to 10Gb) Confocal imaging data Segmentation MR data/ Confocal data Setting up membrane models and tagging to certain nodes. Mesh generation (segmented data and artificial computer generated meshes) Running CardioWave on an external computer Interactive feedback of results Volume Rendering (non regular meshes) Multiple coupled displays (like map3D) SCIRun/CardioWave integration

ECG Simulation NCRR 1. Adapted CardioWave to use FEM models instead of FVM 2. Create a simple FEM model for testing CardioWave and SCIRun visuals rectangular cells connected by gap-junctions (demo) Matlab modules for reading timeseries data into SCIRun 3. Making the Matlab tissue structure generators compatible with the CardioWave simulation requirements and have converters so I can use Matlab to generate a lot of the SCIRun objects (demo) 4. Scaling up the problem to deal with large mesh sizes and a couple of million nodes and elements (bug fixes, stability numerics, etc...) 5. Creating the interface module in SCIRun for controlling CardioWave Done so far.... To do Phase 1: Progress

ECG Simulation NCRR A stream of bundled fields representing: intracellular, extracellular, transmembrane potentials, but possibly as well specific ionic currents or the choice of a membrane model A simulation model captured in a bundled stream with data such as the stiffness matrix, the geometric model, the membrane model assigned to each node, description of the model Select one component of the bundle in this case for displaying. All components have a unique alphanumeric name by which they are identified One component is like a traditional SCIRun dataflow pipe again and all existing tools can be used for visualization Bundled Streams

ECG Simulation NCRR Available soon: MATLAB Interface