Abstract: A medical system includes two or more leadless implantable medical devices, each implanted in a different ventricle of the heart and each including a housing, a first electrode secured relative to the housing, a second electrode secured relative to the housing, and a pressure sensor secured relative to the housing. Each of the leadless implantable medical devices may further include circuitry in the housing operatively coupled to the corresponding first electrode, second electrode, and pressure sensor. The medical system may be configured to determine and store a plurality of pressure-pressure data pairs and/or impedance-impedance data pairs generated by the two or more leadless implantable medical devices, from which a representation of a pressure-pressure loop or volume-volume loop may be determined, to facilitate cardiac resynchronization therapy (CRT), patient health status monitoring, and/or the management of a non-CRT cardiac therapy.

Abstract: An Implantable Medical Device (IMD) configured to be implantable in a ventricle of a patient's heart may include a housing, a first electrode secured relative to the housing, a second electrode secured relative to the housing, the second electrode spaced from the first electrode, and circuitry in the housing operatively coupled to the first electrode and the second electrode. The circuitry may be configured to identify a measure of impedance between the first electrode and the second electrode at each of a plurality of times during a cardiac cycle. Each measure of impedance may represent a measure of volume of the ventricle in which the IMD is implanted. In some cases, the circuitry may generate a pacing pulse, the timing of which is based at least in part on the measure of volume of the ventricle at two or more of the plurality of times during the cardiac cycle.

Abstract: Method and system for determining an atrial contraction timing fiducial in a leadless cardiac pacemaker system is disclosed. An electrical cardiac signal associated with an atrial contraction of the patient's heart and a mechanical response to the atrial contraction of a patient's heart are used to determine an atrial contraction timing fiducial. A ventricle pacing pulse may then be generated an A-V delay after the atrial contraction timing fiducial.

Abstract: An apparatus comprises a respiration sensing circuit configured for coupling electrically to a plurality of electrodes and for sensing a respiration signal representative of respiration of a subject; a signal processing circuit electrically coupled to the respiration sensing circuit and configured to extract a respiration parameter from a sensed respiration signal and determine a signal performance metric for the sensed respiration signal using the respiration parameter; and a control circuit. The control circuit is configured to: initiate sensing of a plurality of respiration signals using different electrode combinations of the plurality of electrodes and determining of the signal performance metric for the sensed respiration signals; and enable an electrode combination from the plurality of electrodes and for use in monitoring respiration of the subject according to the signal performance metric.

Abstract: Methods, devices, and systems for performing pacing capture verification in implantable medical devices such as a leadless cardiac pacemakers using a pressure signal. An example medical device includes a pressure sensor and is configured to monitor for an evoked capture response using the pressure sensor following pace delivery. Various factors of the pressure waveform may be used including the use of threshold, templating, and slope, as well as comparing cross-domain sensed events including using a fiducial point from the pressure signal for comparison to an acoustic, electrical, or motion event, or the use of data obtained from a second device which may be implanted, wearable, or external to the patient.

Abstract: Systems and methods for multi-site cardiac stimulation are disclosed. The system includes an electrostimulation circuit to deliver electrostimulation to one or more candidate sites of at least one heart chamber. The system may sense a physiological signal including during electrostimulation of the heart, use the physiological signal to determine a first stimulation vector for electrostimulation at a first left ventricular (LV) site and a second stimulation vector for electrostimulation at a different second LV site, and determine a therapy mode including a first chronological order and a first timing offset between stimulations delivered according to the first and second stimulation vectors. The electrostimulation circuit may deliver electrostimulation to the heart in accordance with the first and second stimulation vectors and the therapy mode.

Abstract: An example of a system for pacing through multiple electrodes in a ventricle includes a sensing circuit to sense cardiac signal(s), a pacing output circuit to deliver pacing pulses, a heart sound sensor to sense a heart sound signal, and a control circuit to control the delivery of the pacing pulses. The control circuit includes a heart sound detector to detect heart sounds using the heart sound signal, an electrical event detector to detect cardiac electrical events using the cardiac signal(s), a measurement module to measure an optimization parameter using the detected heart sounds, and an optimization module to approximately optimize one or more pacing parameters using the measured optimization parameter. The one or more pacing parameters include an electrode configuration parameter specifying one or more electrodes selected from the multiple electrodes in the ventricle for delivering ventricular pacing pulses to that ventricle.

Abstract: An example of a system for pacing through multiple electrodes in a ventricle includes a sensing circuit to sense cardiac signal(s), a pacing output circuit to deliver pacing pulses, a heart sound sensor to sense a heart sound signal, and a control circuit to control the delivery of the pacing pulses. The control circuit includes a heart sound detector to detect heart sounds using the heart sound signal, an electrical event detector to detect cardiac electrical events using the cardiac signal(s), a measurement module to measure an optimization parameter using the detected heart sounds, an optimization module to perform an optimization procedure using the optimization parameter in response to an optimization command, and an optimization initiator to generate the optimization command. The optimization procedure includes selection of a single electrode or a plurality of electrodes from the multiple electrodes in the ventricle for pacing that ventricle.

Abstract: An apparatus comprises a cardiac signal sensing circuit configured for coupling electrically to a plurality of electrodes and to sense intrinsic cardiac activation at three or more locations within a subject's body using the electrodes; a stimulus circuit configured for coupling to the plurality of electrodes; a signal processing circuit electrically coupled to the cardiac signal sensing circuit and configured to determine a baseline intrinsic activation vector according to the sensed intrinsic cardiac activation; and a control circuit electrically coupled to the cardiac signal sensing circuit and stimulus circuit and configured to: initiate delivery of electrical pacing therapy using initial pacing parameters determined according to the baseline intrinsic activation vector; initiate sensing of a paced activation vector; and adjust one or more pacing therapy parameters according to the paced activation vector.

Abstract: An apparatus comprises a cardiac signal sensing circuit configured to sense a plurality of intrinsic cardiac signals using a plurality of cardiac pacing sites, a heart sound sensing circuit, a stimulus circuit configured to provide an electrical cardiac pacing stimulus to the plurality of pacing sites, and a control circuit electrically coupled to the cardiac signal sensing circuit and the stimulus circuit. The control circuit includes a pacing site locating circuit configured to generate an indication of a preferred pacing site as one of a) a subset of the respective cardiac pacing sites selected using the intrinsic ventricular activation time interval value, from which subset the preferred pacing site is selected using the heart sound characteristic value; or b) a subset of the respective cardiac pacing sites selected using the heart sound characteristic value, from which subset the preferred pacing site is selected using the ventricular activation time interval value.

Abstract: Systems and methods for efficiently determining one or more parameters for vectors of a multi-electrode implantable medical device, and for identifying one or more suitable vectors for sensing cardiac electrical data and/or delivering electrical stimulation therapy based on one or more of the determined parameters. Reducing the time required to determine the one or more parameters for each vector can help reduce procedure time for implanting and/or configuring an implantable medical device, which can reduce costs and/or improved patient comfort.

Abstract: An apparatus comprises a cardiac signal sensing circuit configured to sense a plurality of intrinsic cardiac signals using a plurality of cardiac pacing sites, a heart sound sensing circuit, a stimulus circuit configured to provide an electrical cardiac pacing stimulus to the plurality of pacing sites, and a control circuit electrically coupled to the cardiac signal sensing circuit and the stimulus circuit. The control circuit includes a pacing site locating circuit configured to generate an indication of a preferred pacing site as one of a) a subset of the respective cardiac pacing sites selected using the intrinsic ventricular activation time interval value, from which subset the preferred pacing site is selected using the heart sound characteristic value; or b) a subset of the respective cardiac pacing sites selected using the heart sound characteristic value, from which subset the preferred pacing site is selected using the ventricular activation time interval value.

Abstract: Systems and methods may facilitate selection of a vector for delivering electrical stimulation to a patient's heart. One illustrative method may include delivering electrical stimulation at a first voltage to each vector in a first set of two or more vectors of a multi-vector medical system, determining whether the delivered electrical stimulation at the first voltage resulted in capture for each of the vectors in the first set of two or more vectors, identifying those vectors of the first set of two or more vectors that were determined to result in capture as a second set of vectors, delivering electrical stimulation at a second voltage that is lower than the first voltage to each vector in the second set of vectors, and determining whether the delivered electrical stimulation at the second voltage resulted in capture for each of the vectors in the second set of vectors.

Abstract: An apparatus comprises a stimulus circuit, a cardiac signal sensing circuit, and a control circuit. The stimulus circuit provides electrical pulse energy to a first pacing channel that includes a first left ventricular (LV) electrode as a cathode and a second pacing channel that includes a second LV electrode as a cathode. The cardiac signal sensing circuit senses cardiac signals using a first sensing channel that includes one of the first LV electrode or the second LV electrode. The control circuit includes a capture detection sub-circuit configured to: initiate delivery of electrical pulse energy to both the first pacing channel and the second pacing channel; sense cardiac depolarization of a ventricle using the first sensing channel; determine first and second cardiac capture pulse energy level thresholds for the first and second pacing channels respectively; and provide indications of the cardiac capture pulse energy level thresholds to a user or process.

Abstract: Devices and methods for improving device therapy such as cardiac resynchronization therapy by determining a value for a device parameter are described. An ambulatory medical device (AMD) can include a sensor circuit to sense a physiological signal and generate two or more signal metrics, and detect an event of worsening cardiac condition using the two or more signal metrics. In response to the detection of worsening cardiac condition, the AMD can determine, for a stimulator, a value of at least one stimulation parameter based on temporal responses of two or more signal metrics. The temporal responses include near-term and long-term responses to the stimulation. The AMD can program the stimulator with the determined parameter value, and generate stimulation according to the determined parameter value to stimulate target tissue.

Abstract: Systems and methods may facilitate selection of a vector for delivering electrical stimulation to a patient's heart. One illustrative method may include delivering electrical stimulation at a first voltage to each vector in a first set of two or more vectors of a multi-vector medical system, determining whether the delivered electrical stimulation at the first voltage resulted in capture for each of the vectors in the first set of two or more vectors, identifying those vectors of the first set of two or more vectors that were determined to result in capture as a second set of vectors, delivering electrical stimulation at a second voltage that is lower than the first voltage to each vector in the second set of vectors, and determining whether the delivered electrical stimulation at the second voltage resulted in capture for each of the vectors in the second set of vectors.

Abstract: Systems and methods for selecting one or more sites at or within at least one heart chamber for cardiac stimulation are disclosed. The system can include a physiologic sensor circuit to sense physiologic signals at two or more candidate stimulation sites. The system can generate respective activation timing indicators corresponding to the two or more candidate stimulation sites, and detect MI indicators indicating the presence of, or spatial proximity of each of the two or more candidate stimulation sites to a MI tissue. The system can use the activation timing indicators and the MI indicators to select at least one target stimulation site or to determine an electrostimulation vector. The system can display the selected target stimulation site to a user, or deliver electrostimulation to the patient at the target stimulation site or according to the determined electrostimulation vector.

Abstract: Systems and methods for providing CRT therapy to a patient with an implanted multi-site pacing medical device. In one example, an intrinsic electrical delay associated with each of two or more left ventricle electrodes may be determined. The intrinsic electrical delay associated with each of the two or more left ventricle electrodes may be compared to an electrical delay threshold. If the electrical delay associated with one or fewer left ventricle electrodes is greater than the electrical delay threshold, a single left ventricle electrode may be selected for use during subsequent CRT therapy. If the electrical delay associated with more than one left ventricle electrode is greater than the electrical delay threshold, two or more of the left ventricle electrodes may be selected for use during subsequent CRT therapy.

Abstract: Systems and methods for evaluating multiple candidate electrostimulation vectors for use in therapeutic cardiac stimulation are disclosed. The system can include a programmable electrostimulator circuit for delivering electrostimulation to one or more sites of a heart according to multiple candidate electrostimulation vectors. One or more physiologic sensors can detect resulting physiologic responses to the electrostimulation. A processor circuit can generate categories of indicators including therapy efficacy indicators, battery longevity indicators, or complication indicators using the sensed physiologic responses. The candidate electrostimulation vectors can be ranked according to the categories of indicators in specified orders.

Abstract: Systems and methods for providing CRT therapy to a patient with an implanted multi-site pacing medical device. In one example, an intrinsic electrical delay associated with each of two or more left ventricle electrodes may be determined. The intrinsic electrical delay associated with each of the two or more left ventricle electrodes may be compared to an electrical delay threshold. If the electrical delay associated with one or fewer left ventricle electrodes is greater than the electrical delay threshold, a single left ventricle electrode may be selected for use during subsequent CRT therapy. If the electrical delay associated with more than one left ventricle electrode is greater than the electrical delay threshold, two or more of the left ventricle electrodes may be selected for use during subsequent CRT therapy.