# US 7,613,513 B1 · System and method for determining cardiac geometry > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,613,513 B1 - Document ID: US7613513B1 - Status: Granted - Kind: B1 - Application number: 10/612,770 - Filed: 2003-07-01 - Granted: 2009-11-03 - Earliest claimed: 2003-07-01 - Assignees: Pacesetter, Inc. - Inventors: James E. Brewer; Mark W. Kroll - Web page: https://patentgrep.com/patent/US7613513B1 ## CPC - A61N 1/3627: {for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy} - A61B 5/0295: using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography - A61B 5/1076: {for measuring dimensions inside body cavities, e.g. using catheters (A61B3/1005 takes precedence)} - A61B 5/349: Detecting specific parameters of the electrocardiograph cycle - A61N 1/36507: {controlled by gradient or slope of the heart potential} - A61B 5/0816: {Measuring devices for examining respiratory frequency (measuring frequency of electric signals G01R23/00)} - A61B 5/11: Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb {(A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721)} - A61B 5/145: Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value {; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue} (non-radiation detecting or locating of foreign bodies in blood A61B5/06) - A61N 1/36521: {the parameter being derived from measurement of an electrical impedance} - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract An exemplary method includes delivering an electrical signal to a first position in or adjacent to a cardiac chamber; sensing a potential generated by the delivered electrical signal at a second position; and determining a parameter based, at least in part, on the sensing wherein the parameter relates to cardiac geometry. Other exemplary methods, devices and/or systems are also disclosed. ## Claims ### Claim 1 A method comprising: delivering an electrical signal to a first position using at least a first electrode located in or adjacent to a first cardiac chamber; sensing a potential generated by the delivered electrical signal using at least a second electrode located at a second position in or adjacent to a second cardiac chamber; and determining a change in an inter-electrode spacing between the first electrode and the second electrode based, at least in part, on a percent change of the sensed potential relative to a baseline potential. ### Claim 2 (depends on 1) The method of claim 1, wherein the delivering delivers the electrical signal using a unipolar configuration. ### Claim 3 (depends on 1) The method of claim 1, wherein the first position is in a right ventricle or in a vessel. ### Claim 4 (depends on 1) The method of claim 1, wherein the delivering delivers the electrical signal using a ring electrode. ### Claim 5 (depends on 1) The method of claim 1, Wherein the second position is in a vessel. ### Claim 6 (depends on 1) The method of claim 1, wherein the second position is in a cardiac chamber. ### Claim 7 (depends on 1) The method of claim 1, wherein the sensing senses the potential using a unipolar configuration. ### Claim 8 (depends on 1) The method of claim 1, wherein the sensing occurs during a refractory period. ### Claim 9 (depends on 1) The method of claim 1, wherein the delivering occurs during a refractory period. ### Claim 10 (depends on 1) The method of claim 1, further comprising determining a ventricular volume from the inter-electrode spacing between the first electrode and the second electrode. ### Claim 11 (depends on 1) The method of claim 1, further comprising determining a ventricular distance from the change in the inter-electrode spacing between the first electrode and the second electrode. ### Claim 12 (depends on 1) The method of claim 1, further comprising determining a left ventricular diameter from the change in the inter-electrode spacing between the first electrode and the second electrode. ### Claim 13 (depends on 1) The method of claim 1, further comprising determining a stage of congestive heart failure. ### Claim 14 (depends on 1) The method of claim 1, further comprising delivering cardiac therapy based, at least in part, on the sensing. ### Claim 15 An apparatus comprising: means for delivering an electrical signal to a first position using at least a first electrode located in or adjacent to a first cardiac chamber; means for sensing a potential generated by the delivered electrical signal at a second position using at least a second electrode located in or adjacent to a second cardiac chamber; means for determining a percent change of the sensed potential relative to a baseline potential; and means for determining a change in an inter-electrode spacing between the first electrode and the second electrode based, at least in part, on the percent change of the sensed potential. ### Claim 16 (depends on 15) The apparatus of claim 15 wherein the means for delivering an electrical signal comprises a power source, a lead and an electrode. ### Claim 17 (depends on 15) The apparatus of claim 15 wherein the mean for sensing a potential comprises an electrode, a lead and a circuit. ### Claim 18 (depends on 15) The apparatus of claim 15 wherein the means for determining a change in an inter-electrode spacing comprises an implantable and programmable device. ### Claim 19 An implantable cardiac system comprising: an implantable device having a case capable of acting as an electrode; one or more implantable leads having one or more electrodes wherein the one or more leads are connectable to the device; and circuitry that is operative to deliver an electrical signal to a first electrode position in or adjacent to a first cardiac chamber, sense a potential generated by the delivered electrical signal at a second electrode position in or adjacent to a second cardiac chamber, and a controller adapted to determine a percent change of the sensed potential relative to a baseline potential and to determine a change in an inter-electrode spacing between the first electrode and the second electrode based, at least in part, on the percent change of the sensed potential. ### Claim 20 (depends on 19) The system of claim 19 wherein the one or more implantable leads comprises at least two leads including a first lead that is configured for placement in a right ventricle and a second lead that is configured for placement in a left ventricle. ### Claim 21 (depends on 20) The system of claim 20 wherein the circuitry is operative to deliver an electrical signal to a first electrode carried by the first lead, and to sense a potential generated by the delivered electrical signal at a second electrode carried by the second lead. ### Claim 22 A method comprising: delivering an electrical signal to a first position using a first electrode located in or adjacent to a cardiac chamber using a unipolar electrode configuration; sensing a potential generated by the delivered electrical signal using a second electrode located at a second position; determining a percent change of the sensed potential relative to a baseline potential; and determining a change in an inter-electrode spacing between the first electrode and the second electrode based, at least in part, on the percent change of the sensed potential.