Abstract: The present invention provides a technique for verifying pacing capture of a ventricular chamber, particularly to ensure desired delivery of a ventricular pacing regime (e.g., “CRT”). The invention also provides ventricular capture management by delivering a single ventricular pacing stimulus and checking inter-ventricular conduction during a temporal window to determine if the stimulus captured. If a loss-of-capture LOC) signal results from the capture management testing, then the applied pacing pulses are modified and the conduction test repeated. If LOC, an alert message can issue.

Abstract: Methods and devices for determining optimal Atrial to Ventricular (AV) pacing intervals and Ventricular to Ventricular (VV) delay intervals in order to optimize cardiac output. Impedance, preferably sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change.

Abstract: An implantable medical device and associated method provide atrial pacing and measure an atrial ventricular (AV) delay. An autonomic function index is computed using the AV delay. The autonomic function index may be compiled in a medical report. In some embodiments, the autonomic function index is used to adjust atrial pacing control parameters.

Abstract: Methods and devices for determining optimal Atrial to Ventricular (AV) pacing intervals and Ventricular to Ventricular (VV) delay intervals in order to optimize cardiac output. Impedance, preferably sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change.

Abstract: Methods and devices for determining optimal Atrial to Ventricular (AV) pacing intervals and Ventricular to Ventricular (VV) delay intervals in order to optimize cardiac output. Impedance, preferably sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change.

Abstract: An implantable medical device and associated method provide atrial pacing and measure an atrial ventricular (AV) delay. An autonomic function index is computed using the AV delay. The autonomic function index may be compiled in a medical report. In some embodiments, the autonomic function index is used to adjust atrial pacing control parameters.

Abstract: An implantable cardiac stimulation system and method having continuous capture management capabilities are provided. Continuous capture management is realized by continuously monitoring for secondary effects of loss of capture, thereby effectively providing continuous capture management in any heart chamber without encountering the limitations normally associated with evoked response sensing. A pacing threshold search is triggered upon detecting a secondary indicator of loss of capture. Secondary indicators of loss of capture may be lead-related changes, changes related to the occurrence of atrial sensed events, changes related related to the occurrence of ventricular sensed or paced events, and/or changes related to a monitored physiological condition.

Abstract: Embodiments of the invention provide systems and methods for an implantable medical device comprising means for selecting between an atrial chamber reset (ACR) test and an atrioventricular conduction (AVC) test to provide atrial capture management and means for switching between an atrial-based pacing mode and a dual chamber pacing mode based on detecting relatively reliable atrioventricular conduction.

Abstract: A cardiac stimulation system and associated capture management method are provided in which a safety factor, used in setting pacing pulse output energy, is automatically adjusted in response to the detection of indicators of a likely increase in pacing threshold. The method includes monitoring for increased pacing threshold indicators, which may also be associated with a compromised ability to perform a pacing threshold search. Such indicators may include, but are not limited to, the presence of arrhythmias, arrhythmia episode duration, pacing mode switches, refractory sensed events, and/or lead impedance changes. In response to the detection of a selected indicator of increased pacing threshold, the safety factor is automatically increased. After an increased pacing threshold indicator has not be detected for an interval of time, or if a pacing threshold search yields a result, the safety factor may be restored to a programmed value.

Abstract: Impedance, e.g. sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change. Other methods vary the AA interval to maximize impedance change over the entire cardiac cycle or during the atrial cycle.

Abstract: Techniques for increasing the accuracy of detection of atrial capture may involve determining a ventricular sensing window for ventricular senses associated with atrial test pulses based on observed ventricular senses. For example, an implanted medical device may deliver atrial test pulses to a patient at a time prior to respective atrial pacing pulses to evaluate atrial capture. The implanted medical device observes ventricular senses in response to the atrial test pulses. The implanted medical device may determine a point such as, for example, a midpoint of the ventricular sensing window for the ventricular senses and shift a midpoint of the default ventricular window to the determined midpoint. Further, the implanted medical device may measure patient parameters, such as heart rate and activity level, and determine a ventricular sensing window for ventricular senses associated with atrial test pulses based on the observed ventricular senses and measured patient parameters.

Abstract: An implantable medical device (IMD) includes both evoked response and algorithmic based threshold testing methodologies. The leads used with the IMD are evaluated to determine whether they are high or low polarization. The evoked response methodology is only utilized if the leads are low polarization.

Abstract: A capture detection algorithm detects and distinguishes atrial capture. Atrial chamber reset (ACR) and AV conduction (AVC) algorithms are implemented to measure an atrial pacing threshold The data that is used to choose between ACR and AVC methods is used to determine the progression of the patient's disease state. Some of the significant aspects of the invention include enablement of accurate threshold measurements, including calculation of stability criteria, precise interval measurements and the use of reference interval to determine capture and loss of capture.

Abstract: Methods and devices for determining optimal Atrial to Ventricular (AV) pacing intervals and Ventricular to Ventricular (VV) delay intervals in order to optimize cardiac output. Impedance, preferably sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change.

Abstract: In an atrial pacing system, the A-PACE pulse energy, defined by the pulse width and pulse amplitude, sufficient to reliably capture the atrium without being wasteful of battery energy is periodically determined in accordance with atrial capture management (ACM) algorithms. The ACM algorithms allow a slow intrinsic atrial heart rate that is suppressed by delivered A-PACE pulses resulting in A-CAPTURE and that occurs when delivered test A-PACE pulses result in ALOC to be detected. ALOC is declared if an A-EVENT of the slow intrinsic atrial heart rate is detected either during an ACM test window timed from the last delivered test A-PACE pulse or during delivery of a sequence of test A-PACE pulses delivered within or defining the ACM test window correlated to the slow intrinsic atrial heart rate.

Abstract: A capture detection algorithm in which atrial capture is detected and distinguished. Further, an immediate measurement of the capture threshold is implemented when a pacemaker switches a lead's polarity from bipolar to unipolar in response to a detected lead failure, in either one or both chambers. Atrial chamber reset (ACR) and AV conduction (AVC), implemented to measure an atrial pacing threshold, are comparatively measured to enable measurement of the atrial pacing threshold. The data that is used to choose between ACR and AVC methods is used to determine the progression of the patient's disease state. Some of the significant aspects of the invention include enablement of accurate threshold measurements, including calculation of stability criteria, precise interval measurements and the use of reference interval to determine capture and loss of capture.

Abstract: An implantable cardiac stimulation system and method having continuous capture management capabilities are provided. Continuous capture management is realized by continuously monitoring for secondary effects of loss of capture, thereby effectively providing continuous capture management in any heart chamber without encountering the limitations normally associated with evoked response sensing. A pacing threshold search is triggered upon detecting a secondary indicator of loss of capture. Secondary indicators of loss of capture may be lead-related changes, changes related to the occurrence of atrial sensed events, changes related to the occurrence of ventricular sensed or paced events, and/or changes related to a monitored physiological condition.

Abstract: Techniques for increase the accuracy of detection of atrial capture may involve determining a ventricular sensing window for ventricular senses associated with atrial test pulses based on observed ventricular senses. For example, an implanted medical device may deliver atrial test pulses to a patient at a time prior to respective atrial pacing pulses to evaluate atrial capture. The implanted medical device observes ventricular senses in response to the atrial test pulses. The implanted medical device may determine a point such as, for example, a midpoint of the ventricular sensing window for the ventricular senses and shift a midpoint of the default ventricular window to the determined midpoint. Further, the implanted medical device may measure patient parameters, such as heart rate and activity level, and determine a ventricular sensing window for ventricular senses associated with atrial test pulses based on the observed ventricular senses and measured patient parameters.

Abstract: A capture detection algorithm detects and distinguishes atrial capture. Atrial chamber reset (ACR) and AV conduction (AVC) algorithms are implemented to measure an atrial pacing threshold The data that is used to choose between ACR and AVC methods is used to determine the progression of the patient's disease state. Some of the significant aspects of the invention include enablement of accurate threshold measurements, including calculation of stability criteria, precise interval measurements and the use of reference interval to determine capture and loss of capture.

Abstract: Methods and devices for determining optimal Atrial to Ventricular (AV) pacing intervals and Ventricular to Ventricular (VV) delay intervals in order to optimize cardiac output. Impedance, preferably sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change.