Abstract: A method is disclosed that includes selecting an electrode configuration from a plurality of electrode configurations associated with electrodes of an implantable lead, sensing activity of the right ventricle and the left ventricle, determining an interval between sensed activity of the right ventricle and sensed activity of the left ventricle and determining whether the selected electrode configuration is suitable based at least in part on the interval. In one embodiment, an implantable device performs such a method to improve patient response to the CRT therapy, for example, by selecting a different electrode configuration if the current configuration is not suitable. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: An exemplary method includes providing a filling pressure parameter, providing a perfusion parameter, determining a hemodynamic profile based at least in part on the filling pressure parameter and the perfusion parameter and adjusting a stimulation parameter of an implantable cardiac therapy device based at least in part on the hemodynamic profile. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: Techniques are provided for treating periodic breathing, such as Cheyne-Stokes Respiration, using an implantable medical system. In one technique, diaphragmatic stimulation is delivered during a hyperpnea phase of periodic breathing via electrical stimulation of the phrenic nerves. Diaphragmatic stimulation is synchronized with intrinsic inspiration so as to increase the amplitude of diaphragmatic contraction during inspiration. This tends to decrease intrathoracic pressure leading to occlusion of the respiratory airway. Occlusion reduces actual ventilation during hyperpnea, thus reducing the cyclic blood chemistry imbalance that sustains periodic breathing so as to either mitigate periodic breathing or eliminate it completely. In another technique, respiration is instead inhibited during the hyperpnea phase of periodic breathing by blocking phrenic nerve signals to the extent necessary to reduce ventilation to terminate periodic breathing or at least mitigate its severity.

Abstract: An exemplary method includes acquiring impedance values over one or more respiratory cycles, determining an impedance span based on the impedance values and, based at least in part on the impedance span, determining cardiac condition or respiratory condition. Another exemplary method includes acquiring IEGMs over one or more respiratory cycles, determining evoked response measure values based on the IEGMs, determining an evoked response span based on the evoked response measure values and, based at least in part on the evoked response span, determining cardiac condition or respiratory condition. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: A surface electrocardiogram (EKG) is emulated using signals detected by the internal leads of an implanted device. In one example, the emulation is performed using a technique that concatenates portions of signals sensed using different electrodes, such as by combining far-field ventricular signals sensed in the atria with far-field atrial signals sensed in the ventricles or by combining near-field signals sensed in the atria with near-field signals sensed in the ventricles. In another example, the emulation is performed using a technique that selectively amplifies or attenuates portions of a single signal sensed using a single pair of electrodes, such as by attenuating near-field portions of an atrial unipolar signal relative to far-field portions of the same signal or by attenuating atrial portions of a cross-chamber signal relative to ventricular portions to the same signal.

Abstract: Techniques are provided for detecting the onset of an episode of apnea/hypopnea substantially in real-time. A moving threshold is generated based on recent respiration cycles and differences are accumulated between amplitudes of new respiration cycles and the moving threshold. Apnea/hypopnea is then detected based upon a comparison of the accumulated differences against a fixed threshold. The technique exploits the fact that many episodes of hypopnea begin with a sharp drop in respiration and many episodes of apnea are preceded by a sharp drop in respiration. By accumulating differences between new respiration amplitudes and a short term moving average, any sharp drop in respiration is thereby promptly detected. In many cases, by the time the amplitudes of individual respiration cycles drop to levels directly indicative of apnea/hypopnea, the episode of apnea/hypopnea will have already been detected based upon the sudden sharp drop in respiration amplitude and therapy will have already been initiated.

Abstract: A surface electrocardiogram (EKG) is emulated using signals detected by the internal leads of an implanted device. In one example, the emulation is performed using a technique that concatenates portions of signals sensed using different electrodes, such as by combining far-field ventricular signals sensed in the atria with far-field atrial signals sensed in the ventricles or by combining near-field signals sensed in the atria with near-field signals sensed in the ventricles. In another example, the emulation is performed using a technique that selectively amplifies or attenuates portions of a single signal sensed using a single pair of electrodes, such as by attenuating near-field portions of an atrial unipolar signal relative to far-field portions of the same signal or by attenuating atrial portions of a cross-chamber signal relative to ventricular portions to the same signal.

Abstract: A method and system for programming an implantable therapeutic stimulation device sensing from and delivering therapeutic stimulations to multiple sites within a patient under a plurality of programmable parameters. The method includes automatically determining which parameters need to be programmed, graphically indicating specific parameters that need to be programmed in a spatial correspondence to the affected sites in the patient and/or displaying a waveform corresponding to expected physiological activity with the programming, and providing control inputs to program the specific parameters. The method can also include automatically evaluating the programmed parameters, and if errors exist in the programming, indicating the errors and awaiting corrective input, else programming the implantable device. The method can also include automatically determining a number of sensing and stimulation electrodes connected to the device.

Abstract: An exemplary method includes delivering electrical stimulation to a sympathetic afferent nerve, acquiring information indicative of autonomic tone and, based at least in part on the information, determining if the delivering caused an increase in parasympathetic nerve activity. Various other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: A diagnostic gauge for cardiac health is described. Multiple parameters pertaining to a patent's cardiac health are distilled to a single diagnostic vector having an angle and a magnitude. The diagnostic vector is plotted on a Cartesian graph to form a visual gauge that provides a general assessment of the patient's cardiac health given the underlying parameters. This allows care providers to diagnose more quickly a patient's cardiac health through observation of the gauge without having to review all of the measured parameters. Additionally, the diagnostic gauge can be used to screen for those patient's with conditions that require more immediate attention. A trend of the diagnostic vectors can also be developed and plotted to reveal changes in the patient's cardiac health over time.

Abstract: A programmer and implantable stimulation device system with the implantable device and programmer in telemetric communication with each other wherein the implantable device internally monitors a plurality of physiological parameters and telemeters a plurality of those parameters to the programmer in at least a quasi-real-time manner such that the programmer can display waveforms corresponding to the internally monitored parameters in at least a quasi-real-time manner. The physiological parameters can include measurements of cardiac function, metabolic need, and patient orientation. In some aspects, the internally monitored parameters are provided continuously in a real-time manner and, in other aspects, the parameters are processed to a limited extent and provided as a derived parameter, such as an average, and/or as frames of data.

Abstract: Techniques are provided for overdrive pacing the ventricles using a pacemaker wherein an increase in an overdrive pacing rate is performed primarily to achieve a high degree of rate smoothing. The ventricles are paced at an overdrive pacing rate selected to permit the detection of the least some intrinsic ventricular pulses and then the overdrive pacing rate is dynamically adjusted based on the detected intrinsic ventricular pulses. In one example, an increase in the ventricular overdrive rate is performed only in response to detection of at least two intrinsic ventricular beats within a predetermined search period. If at least two intrinsic ventricular beats are not detected within the search period, the overdrive pacing rate is decreased.

Abstract: An implantable cardiac stimulation device is configured to measure selected ventricular contraction parameters and possibly apply stimulation therapy based on the ventricular contraction parameters. In accordance with one aspect, the ventricular contraction parameters include impedance values that correspond to the volume of fluid in the right ventricle and the left ventricle. In accordance with another aspect, the ventricular contraction parameters include motion values that correspond to heart sounds/motion in the right ventricle and the left ventricle. The ventricular contraction parameters can be used to form pseudo P-V loop from which treatment decisions can be made.

Abstract: An implantable cardiac stimulation device is configured to measure selected ventricular contraction parameters and apply stimulation therapy based on an analysis of the ventricular contraction parameters. The ventricular contraction parameters may include impedance values that correspond to the volume of fluid in the right ventricle and the left ventricle. The ventricular contraction parameters may include motion values that correspond to heart sounds/motion in the right ventricle and the left ventricle. The ventricular contraction parameters can be used to form a ventricular parameter loop associated with one or more cardiac cycles. The total area within the resulting loop should be maintained below a threshold value through the application of applicable stimulation therapy and/or further physician assistance.

Abstract: Techniques are provided for predicting the onset of a heart condition within a patient based on impedance measurements. Briefly, overloads in fluid levels in the thorax and in ventricular myocardial mass within the patient are detected based on impedance signals sensed using implanted electrodes. The onset of certain heart conditions is then predicted based on the overloads. For example, pulmonary edema arising due to diastolic heart failure is predicted based on the detection of on-going overloads in both fluid levels and ventricular mass. Ventricular hypertrophy is detected based on an on-going ventricular mass overload without a sustained fluid overload. Various other heart conditions may also be predicted based on specific combinations of recent or on-going overloads. Evoked response is exploited to corroborate the predictions. Appropriate warning signals are generated and preemptive therapy is initiated.

Abstract: A system and method for estimating optimal atrioventricular delay values for use in pacing the ventricles. Both the intrinsic inter-atrial conduction delay and the intrinsic atrioventricular conduction delay are determined for the patient and then the preferred atrioventricular pacing delay is derived therefrom. By taking into account intrinsic inter-atrial delay along with intrinsic atrioventricular delay, a more reliable estimate of the true optimal atrioventricular delay values for the patient can be achieved than with techniques that only take into account intrinsic atrioventricular delay values. In one example, the technique uses intracardiac electrogram (IEGM) signals and surface electrocardiogram (EKG) signals and hence can be performed by an external programmer without requiring Doppler echocardiography or other cardiac performance monitoring techniques.

Abstract: An implantable cardiac device that delivers electrical therapy to a patient's heart determines if a T wave alternan pattern of the patient's heart exists. The device includes a sensing circuit that generates an electrical signal including T waves representing paced electrical activity of the heart and a morphology detector that measures a metric of each T wave in the electrical signal. A T wave alternan pattern detector determines, responsive to the measured T wave metrics, if a paced activity T wave alternan pattern is present. The T wave alternan pattern detector may also detect for intrinsic T wave alternan patterns. A therapy control initiates suitable different responses for a paced T wave alternan pattern detection and an intrinsic T wave alternan pattern detection.

Abstract: Techniques are provided for treating periodic breathing, such as Cheyne-Stokes Respiration, using an implantable medical system. In one technique, diaphragmatic stimulation is delivered during a hyperpnea phase of periodic breathing via electrical stimulation of the phrenic nerves. Diaphragmatic stimulation is synchronized with intrinsic inspiration so as to increase the amplitude of diaphragmatic contraction during inspiration. This tends to decrease intrathoracic pressure leading to occlusion of the respiratory airway. Occlusion reduces actual ventilation during hyperpnea, thus reducing the cyclic blood chemistry imbalance that sustains periodic breathing so as to either mitigate periodic breathing or eliminate it completely. In another technique, respiration is instead inhibited during the hyperpnea phase of periodic breathing by blocking phrenic nerve signals to the extent necessary to reduce ventilation to terminate periodic breathing or at least mitigate its severity.

Abstract: A system and method are provided for compensating for the drop in blood pressure upon standing. Upon transition from prolonged sitting, lying down, or standing position, the pacemaker abruptly increasing its pacing rate upon postural transition. This pacing rate is triggered when a patient stands after a prolonged reclined or supine/prone position.

Abstract: An implantable cardiac device is programmed to differentiate between central sleep apnea and obstructive sleep apnea. The implantable cardiac device utilizes a respiration-related parameter (e.g., respiration rate, tidal volume, and minute ventilation) to determine whether the patient is experiencing an episode of sleep apnea. When sleep apnea is detected, the implantable cardiac device examines the intracardiac electrogram (IEGM) to classify the apnea as either central sleep apnea or obstructive sleep apnea. The cardiac device may be further configured to administer different therapies depending upon the classification of sleep apnea.