Abstract: A distributed leadless implantable system and method are provided that comprise a leadless implantable medical device (LIMD). The LIMD comprises a housing having a proximal end configured to engage local tissue of interest in a local chamber, cardiac sensing circuitry to sense cardiac signals; and a controller configured to analyze the cardiac signals and, based thereon, to produce a near field (NF) event marker indicative of a local event of interest (EOI) occurring in the local chamber. The system and method further comprise a subcutaneous implantable medical device (SIMD). The SIMD comprises cardiac sensing circuitry to sense cardiac signals, a controller configured to identify a candidate EOI from the cardiac signals, and pulse sensing circuitry to detect the NF event marker from the LIMD. The SIMD controller is configured to declare the candidate EOI as a valid EOI or an invalid EOI based on the NF event marker.

Abstract: During cross-chamber pacing, where anodal capture may not be desirable, pulses are applied between a cathode electrode in a first chamber and an anode electrode in a second chamber. A capture detector detects for capture of the second chamber by the pacing pulses. If capture of the second chamber persists, another electrode is selected as the anodal electrode. During single-chamber pacing, where anodal capture may be desirable, pulses are applied between a cathode electrode and an anode electrode associated with the same chamber. A capture detector detects for capture at both electrodes. If anodal capture is not detected, the energy of the pacing pulse is increased, until anodal capture is detected.

Abstract: Methods, systems and devices described herein can be used for automatically adjusting one or more cardiac resynchronization therapy (CRT) pacing parameters (and more generally stimulation parameters), to achieve a long term reduction in left ventricular (LV) diastolic pressure (and more generally, preload) of a heart failure (HF) patient. A reduction in LV diastolic pressure is indicative of a reduction in preload (the force of blood the fills the left ventricle), which is typically indicative of an improvement in a patient's HF condition. In accordance with certain embodiments, when a set of stimulation parameters is tested, the set is tested for a period that is sufficiently long enough to allow the patient's compensatory mechanisms to react to the set of stimulation parameters and achieve a substantially steady-state LV diastolic pressure corresponding to the using the set of stimulation parameters.

Abstract: Techniques are provided for updating a morphology template used to discriminate abnormal cardiac rhythms. In one example, a non-weighted candidate morphology template is generated based on far-field R-wave morphology. A weighted candidate morphology template is generated based on an ensemble average of the non-weighted candidate morphology template and a previous (i.e. active) morphology template. The previous morphology template is then selectively updated based on a comparison of additional R-waves against both the non-weighted and the weighted candidate templates. Thereafter, abnormal cardiac rhythms such as ventricular tachycardia and supraventricular tachycardia are discriminated using the updated morphology template based on newly-detected far-field R-waves. These techniques provide a method for updating the morphology discrimination template in response to long-term changes in morphology due to cardiac remodeling or cardiac disease progression.

Abstract: Methods, systems and devices described herein can be used for automatically adjusting one or more cardiac resynchronization therapy (CRT) pacing parameters (and more generally stimulation parameters), to achieve a long term reduction in left ventricular (LV) diastolic pressure (and more generally, preload) of a heart failure (HF) patient. A reduction in LV diastolic pressure is indicative of a reduction in preload (the force of blood the fills the left ventricle), which is typically indicative of an improvement in a patient's HF condition. In accordance with certain embodiments, when a set of stimulation parameters is tested, the set is tested for a period that is sufficiently long enough to allow the patient's compensatory mechanisms to react to the set of stimulation parameters and achieve a substantially steady-state LV diastolic pressure corresponding to the using the set of stimulation parameters.

Abstract: A method and system are provided for characterizing chamber specific function. The method and system comprise collecting cardiac signals associated with asynchronous timing between first and second chambers of the heart; collecting dynamic impedance (DI) data along a chamber-specific function (CSF) vector to form a DI data set, the DI data set collected during a collection window that is temporally aligned based on a timing feature of interest (FOI); repeating the collection operations over multiple cardiac cycles (CC) to obtain an ensemble of DI data sets; and combining the ensemble of DI data sets to form a composite DI data set that is coupled to a chamber functional mechanic of interest (FMOI) associated with the first chamber and decoupled from functional mechanics associated with the second chamber; and analyzing the composite DI data set to obtain a CSF indicator associated with the chamber FMOI of the first chamber.

Abstract: A method and system are provided for characterizing cardiac function. The method and system comprise collecting cardiac signals associated with electrical or mechanical behavior of a heart over at least one cardiac cycle; identifying a timing feature of interest (FOI) from the cardiac signals; collecting dynamic impedance (DI) data over at least one cardiac cycle (CC), designated by the timing FOI, along at least one of i) a venous return (VR) vector or ii) a right ventricular function (RVF) vector; and analyzing at least one morphologic characteristic from the DI data based on at least one of i) a VR-DI correlation metric to obtain a VR indicator associated with the CC or ii) a RVF-DI correlation metric to obtain a RVF indicator associated with CC.

Abstract: An implantable medical device, comprised of at least one lead configured to be located proximate to a heart, the at least one lead including electrodes, at least a portion of the electrodes configured to sense cardiac activity. A therapy module configured to control delivery of pacing pulses in accordance with a therapy timing and based on the cardiac sensed activity sensed. Cardiac impedance (CI) sensor circuitry configured to be coupled to at least a first combination of the electrodes to sense cardiac impedance (CI), the CI sensor circuitry generating an impedance data stream associated with a corresponding CI sensing vector.

Abstract: A method and system are provided for characterizing chamber specific function. The method and system comprise collecting cardiac signals associated with asynchronous timing between first and second chambers of the heart; collecting dynamic impedance (DI) data along a chamber-specific function (CSF) vector to form a DI data set, the DI data set collected during a collection window that is temporally aligned based on a timing feature of interest (FOI); repeating the collection operations over multiple cardiac cycles (CC) to obtain an ensemble of DI data sets; and combining the ensemble of DI data sets to form a composite DI data set that is coupled to a chamber functional mechanic of interest (FMOI) associated with the first chamber and decoupled from functional mechanics associated with the second chamber; and analyzing the composite DI data set to obtain a CSF indicator associated with the chamber FMOI of the first chamber.

Abstract: A method and system for differential analysis of cardiac events are provided that include monitoring cardiac signals from a heart to detect deviations indicative of at least one of ischemia and myocardial infarction (MI). The method and system also monitor physiologic surrogate signals associated with pain to detect chest pain. Additionally, the method and system include characterizing a cardiac event exhibited by the heart based on whether the cardiac event occurs in a presence of at least one of the ischemia, IM, and chest pain.

Abstract: An implantable medical device, comprised of at least one lead configured to be located proximate to a heart, the at least one lead including electrodes, at least a portion of the electrodes configured to sense cardiac activity. A therapy module configured to control delivery of pacing pulses in accordance with a therapy timing and based on the cardiac sensed activity sensed. Cardiac impedance (CI) sensor circuitry configured to be coupled to at least a first combination of the electrodes to sense cardiac impedance (CI), the CI sensor circuitry generating an impedance data stream associated with a corresponding CI sensing vector.

Abstract: Techniques are provided for use with an implantable medical device for detecting and assessing heart failure and for controlling cardiac resynchronization therapy (CRT) based on impedance signals obtained using hybrid impedance configurations. The hybrid configurations exploit right atrial (RA)-based impedance measurement vectors and/or left ventricular (LV)-based impedance measurement vectors. In one example, current is injected between the device case and a ring electrode in the right ventricle (RV) or RA. RA-based impedance values are measured along vectors between the device case and an RA electrode. LV-based impedance values are measured along vectors between the device case and one or more electrodes of the LV. Heart failure and other cardiac conditions are detected and tracked using the measured impedance values. CRT delay parameters are also optimized based impedance.

Abstract: Techniques are provided for controlling neurostimulation such as spinal cord stimulation (SCS) using a cardiac rhythm management device (CRMD). In various examples described herein, neurostimulation is delivered to a patient while regional cardiac performance of the heart of the patient is assessed by the CRMD. The delivery of further neurostimulation is adjusted or controlled based, at least in part, on the regional cardiac performance, preferably to enhance positive effects on the heart due to the neurostimulation or to mitigate any negative effects. Regional cardiac performance is assessed based on parameters derived from cardiogenic impedance signals detected along various vectors through the heart.

Abstract: Techniques are provided for updating a morphology template used to discriminate abnormal cardiac rhythms. In one example, a non-weighted candidate morphology template is generated based on far-field R-wave morphology. A weighted candidate morphology template is generated based on an ensemble average of the non-weighted candidate morphology template and a previous (i.e. active) morphology template. The previous morphology template is then selectively updated based on a comparison of additional R-waves against both the non-weighted and the weighted candidate templates. Thereafter, abnormal cardiac rhythms such as ventricular tachycardia and supraventricular tachycardia are discriminated using the updated morphology template based on newly-detected far-field R-waves. These techniques provide a method for updating the morphology discrimination template in response to long-term changes in morphology due to cardiac remodeling or cardiac disease progression.

Abstract: Techniques are provided for controlling neurostimulation such as spinal cord stimulation (SCS) using a cardiac rhythm management device (CRMD). In various examples described herein, neurostimulation is delivered to a patient while regional cardiac performance of the heart of the patient is assessed by the CRMD. The delivery of further neurostimulation is adjusted or controlled based, at least in part, on the regional cardiac performance, preferably to enhance positive effects on the heart due to the neurostimulation or to mitigate any negative effects. Regional cardiac performance is assessed based on parameters derived from cardiogenic impedance signals detected along various vectors through the heart.

Abstract: Techniques are provided for use with an implantable medical device for detecting and assessing heart failure and for controlling cardiac resynchronization therapy (CRT) based on impedance signals obtained using hybrid impedance configurations. The hybrid configurations exploit right atrial (RA)-based impedance measurement vectors and/or left ventricular (LV)-based impedance measurement vectors. In one example, current is injected between the device case and a ring electrode in the right ventricle (RV) or RA. RA-based impedance values are measured along vectors between the device case and an RA electrode. LV-based impedance values are measured along vectors between the device case and one or more electrodes of the LV. Heart failure and other cardiac conditions are detected and tracked using the measured impedance values. CRT delay parameters are also optimized based impedance.

Abstract: Detection of T wave oversensing in an ICD is accomplished in order to prevent improper application of treatment to a patient. The ICD device senses for electrical impulses representing the R waves of a beating heart. In some instances the ICD device will sense T waves that it will assume to be R waves, because the ICD device expects or assumes that such sensed signals are R waves. Time intervals between each detected, assumed R waves are measured and a list of intervals is generated. The list is transformed into its frequency domain equivalent and analyzed for peaks and randomness criteria to determine whether T wave oversensing has occurred.

Abstract: An implantable medical device includes a lead, a pulse generator, an autothreshold module and a control module. The lead includes electrodes positioned within a heart. At least one of the electrodes senses cardiac signals. The pulse generator delivers a stimulus pulse through at least one of the electrodes. The autothreshold module performs a threshold search when operating in an autothreshold mode and causes atrial stimulus pulses to be delivered in an atrium of the heart at an overdrive rate during the threshold search. The control module determines an AV conduction time and applies an overdrive AV adjustment to the AV conduction time to generate an AV delay. The autothreshold module uses the AV delay in connection with delivering ventricular stimulus pulses to a ventricle of the heart.

Abstract: An implantable medical device includes a lead, a pulse generator, an autocapture module, an autothreshold module, a fusion detection module, and a control module. The lead includes electrodes configured to be positioned within a heart. At least one of the electrodes is capable of sensing cardiac signals. The pulse generator delivers a stimulus pulse through at least one of the electrodes. The autocapture module senses an evoked response of the heart after delivery of the stimulus pulse when operating in an autocapture mode. The autothreshold module performs a threshold search when operating in an autothreshold mode. The fusion detection module identifies fusion-based behavior in the heart. The control module automatically switches between the autothreshold and autocapture modes based on a presence of the fusion-based behavior.

Abstract: Detection of T wave oversensing in an ICD is accomplished in order to prevent improper application of treatment to a patient. The ICD device senses for electrical impulses representing the R waves of a beating heart. In some instances the ICD device will sense T waves that it will assume to be R waves, because the ICD device expects or assumes that such sensed signals are R waves. Time intervals between each detected, assumed R waves are measured and a list of intervals is generated. The list is transformed into its frequency domain equivalent and analyzed for peaks and randomness criteria to determine whether T wave oversensing has occurred.