Using implantable medical devices to augment noninvasive cardiac mapping

Abstract

An example method includes establishing a communications link between an electrophysiology (EP) monitoring system and an implantable medical device (IMD). IMD electrical data is received at the monitoring system via the communications link. The IMD electrical data may be synchronized with EP measurement data to provide synchronized electrical data based on timing of a synchronization signal sensed by an IMD electrode and/or EP electrodes. The method also includes computing reconstructed electrical signals for locations on a surface of interest within the patient's body based on the synchronized electrical data and geometry data. The geometry data represents locations of the EP electrodes, a location of the IMD electrode within the patient's body and the surface of interest.

What is claimed is: 
     
         1 . A system comprising:
 an implantable medical device (IMD) comprising an IMD electrode and IMD circuitry, wherein the IMD electrode is adapted to be positioned within a patient's body, and the IMD circuitry is coupled to the IMD electrode and adapted to provide IMD electrical data based on an electrical signal sensed by the IMD electrode and to deliver an electrical signal through the IMD electrode; and   an electrophysiology (EP) monitoring system comprising:
 non-transitory memory to store the IMD electrical data, EP electrical data, and geometry data, the EP electrical data representing signals measured by EP electrodes; and 
 a processor coupled to the memory to access data and instructions stored in the memory, the instructions programmed to at least:
 establish a communications link between the EP monitoring system and the IMD; 
 receive the IMD electrical data at the EP monitoring system through the communications link; 
 analyze the IMD electrical data and the EP electrical data to identify a feature of at least one signal represented by the IMD electrical data and the EP electrical data; 
 synchronize the IMD electrical data and the EP electrical data based on the identified feature and provide synchronized electrical data representative of time-synchronized electrical signals sensed by the IMD electrode and the EP electrodes; and 
 compute a map of electrical signals for locations on a surface of interest within the patient's body based on the synchronized electrical data and the geometry data, the geometry data representing locations of the EP electrodes, a location of the IMD electrode, and geometry of the surface of interest. 
 
   
     
     
         2 . The system of  claim 1 , wherein the identified feature of the EP signal includes a morphology and/or timing of the at least one signal. 
     
     
         3 . The system of  claim 1 , wherein the IMD includes a plurality of IMD electrodes adapted to be positioned at respective locations within the patient's body, and the instructions are further programmed to:
 control the IMD through the communications link to provide respective signals from different ones of the IMD electrodes;   store electrical signal data measured by the EP electrodes responsive to the respective signals; and   reconstruct EP signals across the surface of interest based on the stored electrical signal data measured by the EP electrodes, responsive to the respective signals and the geometry data, in which the reconstructed EP signals are representative of effects of each of the respective signals on cardiac tissue.   
     
     
         4 . The system of  claim 3 , wherein:
 the respective signals are provided by the IMD with varying signal parameters, and   the reconstructed EP signals at one or more regions that are representative of the effects of each of the respective signals at locations different from where the respective signals are applied and/or across an entire surface of the patient's heart.   
     
     
         5 . The system of  claim 3 , wherein the respective signals are respective pacing signals applied at the different locations corresponding to the locations of the electrodes, and the instructions are further programmed to:
 compute an impedance correction matrix based on EP electrical data measured responsive to the pacing signals applied at each of the different locations; and   correct regions across the surface of interest, which were not paced, based on the impedance correction matrix.   
     
     
         6 . The system of  claim 5 , wherein the instructions are further programmed to:
 calibrate model data to characterize inhomogeneities of the patient's body between the surface of interest and an outer surface of the patient's body based on the impedance correction matrix, and   compute the map of electrical signals for locations residing on the surface of interest based on the calibrated model data.   
     
     
         7 . The system of  claim 6 , wherein the instructions are further programmed to:
 calculate a transfer matrix based on the geometry data and the calibrated model data,   wherein the map of electrical signals comprises a map reconstructed electrical signals on the surface of interest computed based on the transfer matrix and the synchronized electrical data.   
     
     
         8 . The system of  claim 1 , wherein the instructions are further programmed to:
 send program instructions to the IMD over the communications link to control the IMD to provide a stimulus signal from the IMD electrode to implement a cardiac therapy based on control parameters included in the program instructions;   generate the map of electrical signals representative of cardiac electrical activity responsive to the control parameters;   repeat the sending of program instructions and generating the map to provide respective maps of electrical signals across for different control parameters; and   determine a set of the control parameters to configure the IMD to implement the cardiac therapy based on an evaluation of the respective maps.   
     
     
         9 . The system of  claim 1 , wherein the instructions to compute the map of electrical signals for locations residing on the surface of interest include instructions to reconstruct the electrical signals on the surface of interest by solving an inverse problem based on the geometry data and the synchronized electrical data, the instructions are further programmed to:
 spatially align a region or points in the reconstructed electrical signals corresponding to one or more cardiac locations where an instance of a cardia event recorded by the IMD electrode was represented in the IMD electrical data; and   compare the reconstructed electrical signals for an other detected instance of the cardiac event with a prior instance of the cardiac event to determine an accuracy of the reconstructed electrical signals.   
     
     
         10 . The system of  claim 9 , wherein the instructions are further programmed to adjust the instructions to reconstruct the electrical signals based on the comparison so that the reconstructed electrical signals better match signals recorded by the IMD for the event. 
     
     
         11 . The system of  claim 10 , wherein the instructions to adjust the instructions are further programmed to adjust the reconstructed electrical signals spatially to minimize a difference between the reconstructed electrical signals and the signals recorded by the IMD for the other detected instance of the cardiac event. 
     
     
         12 . The system of  claim 10 , wherein the instructions to adjust are further programmed to weight respective locations in a transfer function used to solve the inverse problem based on a correlation between locations of reconstructed signals and the signals recorded by the IMD, and using the adjusted weights in the transfer function to reconstruct the electrical signals on the surface of interest. 
     
     
         13 . The system of  claim 1 , wherein the IMD comprises a leadless IMD. 
     
     
         14 . The system of  claim 1 , further comprising:
 a non-invasive sensor apparatus including respective EP electrodes, the sensor apparatus configured to position the respective electrodes on the surface of the patient's body; and   a communications module configured to communicate with the IMD over the communications link.   
     
     
         15 . One or more non-transitory computer-readable media having instructions, which when executed by a processor, cause the processor to at least:
 establish a communications link between an electrophysiological (EP) monitoring system and an implantable medical device (IMD) including an IMD electrode;   receive IMD electrical data at the EP monitoring system through the communications link;   analyze the IMD electrical data and the EP electrical data to identify a feature of at least one signal represented by the IMD electrical data and the EP electrical data;   synchronize the IMD electrical data and the EP electrical data based on the identified feature and provide synchronized electrical data representative of time-synchronized electrical signals sensed by the IMD electrode and the EP electrodes; and   compute a map of electrical signals for locations residing on a surface of interest within a patient's body based on the synchronized electrical data and geometry data, the geometry data representing locations of the EP electrodes, a location of the IMD electrode, and geometry of the surface of interest.   
     
     
         16 . The media of  claim 15 , wherein the IMD includes a plurality of IMD electrodes, and the instructions are further programmed to:
 control the IMD through the communications link to provide respective signals from different ones of the IMD electrodes;   store electrical signal data measured by the EP electrodes responsive to the respective signals; and   reconstruct EP signals across the surface of interest based on the stored electrical signal data measured by the EP electrodes, responsive to the respective signals and the geometry data, in which the reconstructed EP signals are representative of effects of each of the respective signals on cardiac tissue.   
     
     
         17 . The media of  claim 16 , wherein the respective signals are applied at different locations corresponding to locations of the electrodes, and the instructions are further programmed to:
 compute an impedance correction matrix based on EP electrical data measured responsive to the respective signals applied at each of the different locations;   correct regions across the surface of interest, which were not paced, based on the impedance correction matrix;   calibrate model data to characterize inhomogeneities of the patient's body between the surface of interest and the surface of the patient's body based on the impedance correction matrix, and   compute the map of electrical signals for locations residing on the surface of interest based on the calibrated model data.   
     
     
         18 . The media of  claim 15 , wherein the instructions are further programmed to:
 send program instructions to the IMD over the communications link to control the IMD to provide a stimulus signal from the IMD electrode to implement a cardiac therapy based on control parameters included in the program instructions;   generate the map of electrical signals representative of cardiac electrical activity responsive to the control parameters;   repeat the sending of program instructions and generating the map to provide respective maps of electrical signals across for different control parameters; and   determine a set of the control parameters to configure the IMD to implement the cardiac therapy based on an evaluation of the respective maps.   
     
     
         19 . The media of  claim 15 , wherein the instructions to compute the map of electrical signals for locations residing on the surface of interest include instructions to reconstruct the electrical signals on the surface of interest by solving an inverse problem based on the geometry data and the synchronized electrical data, the instructions are further programmed to:
 spatially align a region or points in the reconstructed electrical signals corresponding to one or more cardiac locations where an instance of a cardiac event recorded by the IMD electrode was represented in the IMD electrical data;   compare the reconstructed electrical signals for an other detected instance of the cardiac event with a prior instance of the cardiac event to determine an accuracy of the reconstructed electrical signals; and   adjust the instructions to reconstruct the electrical signals based on the comparison so that the reconstructed electrical signals better match the signals recorded by the IMD for the event.   
     
     
         20 . The media of  claim 19 , wherein the instructions to adjust are further programmed to weight respective locations in a transfer function used to solve the inverse problem based on a correlation between locations of the reconstructed electrical signals and the signals recorded by the IMD, and using the adjusted weights in the transfer function to reconstruct the electrical signals on the surface of interest.