# US 2014/0194943 A1 · Rate initialization and overdrive pacing for capture threshold testing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0194943 A1 - Document ID: US20140194943A1 - Status: Published application - Kind: A1 - Application number: 14/223,347 - Filed: 2014-03-24 - Published: 2014-07-10 - Earliest claimed: 2010-12-23 - Assignees: Cardiac Pacemakers, Inc. - Applicants: Cardiac Pacemakers, Inc. - Inventors: Eric K. Enrooth; Sunipa Saha; Clayton S. Foster; Yanting Dong - Web page: https://patentgrep.com/patent/US20140194943A1 ## CPC - A61N 1/371: {Capture, i.e. successful stimulation} - A61N 1/3714: {Atrial capture} - 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) ## Abstract Approaches for rate initialization and overdrive pacing used during capture threshold testing are described. Cardiac cycles are detected and the cardiac events of a cardiac chamber that occur during the cardiac cycles are monitored. The number of intrinsic beats in the cardiac events is counted. Initialization for a capture threshold test involves maintaining a pre-test pacing rate for the capture threshold test if the number of intrinsic beats in the cardiac events is less than a threshold. The pacing rate is increased for the capture threshold test if the number of intrinsic beats in the cardiac events is greater than the threshold. ## Claims ### Claim 1 A method of operating a cardiac device, comprising: delivering pacing pulses to one or more electrodes that are coupleable to a cardiac chamber of a heart at a first pacing rate, and counting a number of intrinsic and/or fusion beats over a plurality of cardiac cycles; after the counting step, initializing a capture threshold test (CTT) including setting a capture threshold test (CTT) pacing rate, wherein the capture threshold test (CTT) pacing rate is set to a second pacing rate that is higher than the first pacing rate if the number of counted intrinsic and/or fusion beats over the plurality of cardiac cycles reaches a predetermined threshold; and executing the capture threshold test (CTT) using the initialized capture threshold test (CTT) pacing rate. ### Claim 2 (depends on 1) The method of claim 1, further comprising limiting the second pacing rate from going beyond a predetermined maximum pacing rate. ### Claim 3 (depends on 1) The method of claim 1, wherein the plurality of cardiac cycles is a predetermined number of cardiac cycles. ### Claim 4 (depends on 1) The method of claim 1, wherein the plurality of cardiac cycles are a plurality of consecutive cardiac cycles. ### Claim 5 (depends on 4) The method of claim 4, wherein the capture threshold test (CTT) pacing rate is set to the first pacing rate if the number of counted intrinsic and/or fusion beats over the plurality of cardiac cycles does not reach the predetermined threshold. ### Claim 6 (depends on 1) The method of claim 1, further comprises detecting cardiac cycle end events. ### Claim 7 (depends on 1) The method of claim 1 further comprises detecting cardiac events including atrial events, and wherein the counted intrinsic and/or fusion beats are intrinsic and/or fusion atrial beats, and the capture threshold test (CTT) pacing rate corresponds to an atrial pacing rate. ### Claim 8 (depends on 1) The method of claim 1 further comprises detecting cardiac events including ventricular events, and wherein the counted intrinsic and/or fusion beats are intrinsic and/or fusion ventricular beats, and the capture threshold test (CTT) pacing rate corresponds to a ventricular pacing rate. ### Claim 9 (depends on 1) The method of claim 1, wherein the counting step counts the number of intrinsic beats over the plurality of cardiac cycles. ### Claim 10 (depends on 1) The method of claim 1, wherein the counting step counts the number of fusion beats over the plurality of cardiac cycles. ### Claim 11 (depends on 1) The method of claim 1, wherein the counting step counts the number of intrinsic beats and fusion beats over the plurality of cardiac cycles. ### Claim 12 A cardiac device, comprising: pacing circuitry for delivering pacing pulses to a cardiac chamber; sensing circuitry configured to detect cardiac events; a controller operatively coupled to the pacing circuitry and the sensing circuitry; the controller configured to determine from the detected cardiac events a number of intrinsic and/or fusion beats and count the number of intrinsic and/or fusion beats over a plurality of cardiac cycles; the controller further configured to set a capture threshold test (CTT) pacing rate for a capture threshold test (CTT), wherein the capture threshold test (CTT) pacing rate is set higher if the number of counted intrinsic and/or fusion beats reaches a predetermined threshold while limiting the capture threshold test (CTT) pacing rate from going beyond a predetermined maximum pacing rate; and the controller further configured to initiate a capture threshold test (CTT) at the capture threshold test (CTT) pacing rate by delivering pacing pulses to the cardiac chamber using the pacing circuitry. ### Claim 13 (depends on 12) The cardiac device of claim 12, wherein the plurality of cardiac cycles is a predetermined number of cardiac cycles. ### Claim 14 (depends on 12) The cardiac device of claim 12, wherein the plurality of cardiac cycles are a plurality of consecutive cardiac cycles. ### Claim 15 (depends on 12) The cardiac device of claim 12, wherein the number of counted intrinsic and/or fusion beats corresponds to the number of intrinsic and/or fusion beats that occur in consecutive cardiac cycles. ### Claim 16 (depends on 12) The cardiac device of claim 12, wherein the controller is configured to maintain a previous pacing rate as the capture threshold test (CTT) pacing rate if the number of counted intrinsic and/or fusion beats does not reach the predetermined threshold. ### Claim 17 A cardiac device, comprising: pacing circuitry for delivering pacing pulses to a heart chamber; sensing circuitry configured to detect cardiac signals that include indications of cardiac events during a plurality of cardiac cycles; and a controller coupled to the pacing circuitry and the sensing circuitry, the controller configured to count a number of intrinsic beats in the cardiac events, the controller further configured to set a capture threshold test (CTT) pacing rate for a capture threshold test (CTT), wherein the capture threshold test (CTT) pacing rate is set at a first pacing rate if the number of intrinsic beats in the cardiac events does not go beyond a predetermined threshold and the capture threshold test (CTT) pacing rate is set higher at a second pacing rate if the number of intrinsic beats in the cardiac events goes beyond the predetermined threshold; and the controller is further configured to initiate a capture threshold test (CTT) at the capture threshold test (CTT) pacing rate by delivering pacing pulses to the heart chamber using the pacing circuitry. ### Claim 18 (depends on 17) The cardiac device of claim 17, wherein the controller limits the capture threshold test (CTT) pacing rate from going beyond a predetermined maximum pacing rate. ### Claim 19 (depends on 17) The cardiac device of claim 17, wherein the controller is configured to repeatedly count the number of intrinsic beats in the cardiac events, and set the capture threshold test (CTT) pacing rate to higher pacing rate if the number of intrinsic beats in the cardiac events goes beyond the predetermined threshold until the number of intrinsic beats in the cardiac events does not go beyond the predetermined threshold or until a predetermined maximum pacing rate is reached. ### Claim 20 (depends on 19) The cardiac device of claim 19, wherein after the number of intrinsic beats in the cardiac events does not go beyond the predetermined threshold, the controller is configured to initiate the capture threshold test (CTT) at the capture threshold test (CTT) pacing rate.