Abstract: Implantable systems, and methods for use therein, perform at least one of a cardiac assessment and an autonomic assessment. Short-term fluctuations in PR intervals, that follow the premature contractions in the ventricles, are monitored. At least one of a cardiac assessment and an autonomic assessment is performed based on the monitored fluctuations in PR intervals that follow the premature contractions in the ventricles. This can include assessing a patient's risk of sudden cardiac death (SCD), assessing a patient's autonomic tone and/or detecting myocardial ischemic events based on the monitored fluctuations in PR intervals that follow the premature contractions in the ventricles.

Abstract: An implantable cardiac device minimizes apnea burden. In one implementation, the device administers a series of cardiac pacing trials using a different value for a pacing parameter in each trial and then measures an apnea burden corresponding to each trial in order to determine a value which reduces apnea burden when used for ongoing cardiac pacing. In one implementation the implantable cardiac device performs series of trials in cycles, during which a first series of trials determines a value for a first pacing parameter for reducing apnea burden while other pacing parameters are held constant. Subsequent series of trials subject the other pacing parameters, in turn, to their own series of pacing trials while holding the non-subjected pacing parameters constant. Through multiple cycles, the device optimizes each parameter in turn based on continually improving values for the other pacing parameters.

Abstract: Implantable systems, and methods for use therein, perform at least one of a cardiac assessment and an autonomic assessment. Short-term fluctuations in PR intervals, that follow the premature contractions in the ventricles, are monitored. At least one of a cardiac assessment and an autonomic assessment is performed based on the monitored fluctuations in PR intervals that follow the premature contractions in the ventricles. This can include assessing a patient's risk of sudden cardiac death (SCD), assessing a patient's autonomic tone and/or detecting myocardial ischemic events based on the monitored fluctuations in PR intervals that follow the premature contractions in the ventricles.

Abstract: A method of predicting a patient's response to multi-chamber pacing by implanting at least three sensing electrodes, measuring across at least two different impedance vectors of the heart via the three electrodes to obtain at least two impedance signals, and evaluating the at least two impedance signals for indications of contractile dysynchrony. Contractile dysynchrony indicates that the patient is likely to have a positive response to multi-chamber pacing. Also an implantable cardiac stimulation device with an implantable housing, a stimulation pulse generator positioned within the housing, at least two implantable leads, and a controller communicating with the pulse generator to induce the generator to deliver therapeutic stimulation to a patient's heart. The leads are arranged to measure a physiological parameter along at least two different spatial orientations.

Abstract: Techniques are provided for monitoring thoracic fluid levels based on thoracic impedance (ZT) and cardiogenic impedance (ZC). In one example, the implantable device tracks the maximum time rate of change in cardiogenic impedance (i.e. max(dZC/dt)) to detect trends toward hypervolemic or hypovolemic states within the patient based on changes in heart contractility. The detection of these trends in combination with trends in thoracic impedance allows for a determination of whether the thoracic cavity of the patient is generally “too wet” or “too dry,” and thus allows for the titration of diuretics to avoid such extremes. In particular, a decrease in thoracic impedance (ZT) in combination with a decrease in max (dZC/dt) is indicative of the thorax being “too wet” (i.e. a fluid overload). Conversely, an increase in thoracic impedance (ZT) in combination with a decrease in max (dZC/dt) is indicative of the thorax being “too dry” (i.e. a fluid underload).

Abstract: Techniques are provided for evaluating and optimizing the contribution of particular heart chambers to pacing efficacy. Briefly, a pacemaker temporarily alters the mode with which pacing therapy is delivered so as to selectively alter the heart chambers that are paced. The pacemaker detects any transient changes in pacing efficacy following the alteration in pacing mode. The pacemaker then assesses the contribution of particular heart chambers to pacing efficacy based on the alteration in the pacing mode and on any transient changes in the pacing efficacy. Additionally, techniques are provided herein for automatically adjusting pacing parameters to optimize the contribution of particular chambers to pacing efficacy.

Abstract: An exemplary method includes calling for delivery of energy to one or more electrodes positionable proximate to an autonomic pathway to alter tone of the geniglossus muscle. Such a method may maintain or alter upper airway patency and, in turn, prevent or alleviate obstructive apnea. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: Exemplary techniques for determining patient posture from cardiac data sensed by an implantable medical device (IMD) are described. One technique involves sensing intracardiac electrogram (IEGM) data from a patient and determining a posture of the patient from the sensed IEGM data. The technique then considers the posture in formulating patient therapy.

Abstract: Techniques are provided for evaluating and optimizing the contribution of particular heart chambers to pacing efficacy. Briefly, a pacemaker temporarily alters the mode with which pacing therapy is delivered so as to selectively alter the heart chambers that are paced. The pacemaker detects any transient changes in pacing efficacy following the alteration in pacing mode. The pacemaker then assesses the contribution of particular heart chambers to pacing efficacy based on the alteration in the pacing mode and on any transient changes in the pacing efficacy. Additionally, techniques are provided herein for automatically adjusting pacing parameters to optimize the contribution of particular chambers to pacing efficacy.

Abstract: Embodiments of the present invention relate to implantable systems, and methods for use therewith, for monitoring myocardial mechanical stability based on a signal that is indicative of mechanical functioning of a patient's heart for a plurality of consecutive beats. Certain embodiments use time domain techniques, while other embodiments use frequency domain techniques, to monitor myocardial mechanical stability. In certain embodiments the patient's heart is paced using a patterned pacing sequence that repeats every N beats. In other embodiments, the patient's heart need not be paced. This abstract is not intended to be a complete description of, or limit the scope of, the invention.

Abstract: A method and system are provided for providing coordinated ventricular overdrive and triggered pacing through an implantable system. A lead senses signals from a heart to obtain sensed signals representative of tachycardia occurring in at least one chamber of the heart. The lead includes an electrode. A control module detects tachycardia in at least one chamber of the heart and based thereon, initiates an overdrive pacing mode and a triggered pacing mode. The control module controls delivery of overdrive pacing pulses through the electrode to a first chamber of the heart in accordance with the overdrive pacing mode. The control module controls delivery of a triggered pacing pulse through the electrode to the first chamber of the heart in accordance with the triggered pacing mode. The triggered pacing pulse is temporally interspersed with the overdrive pacing pulses. The triggered pacing pulse may be delivered at a time that is independent of, and unrelated to, the timing of the overdrive pacing pulses.

Abstract: An implantable system applies tiered antitachycardia pacing (ATP) that may be combined with pre-pulsing therapy in order to reduce pain. In one implementation, an exemplary system applies a progression of increasingly potent pacing vectors, progressing in an initial tier from small electrodes inside the heart to later tiers that increasingly use a large electrode surface outside the heart. In the latter tiers, a pre-pulse may be added prior to each ATP pulse to reduce the sensation of pain.

Abstract: A device and methods for automatically evaluating one or more patient physiological parameters and, upon determination that certain therapies are indicated, delivering therapeutic mechanical stimulations to tissue of the patient. The mechanical stimulations generally include vibrations delivered at frequencies somewhat higher or lower than an intrinsic frequency and the therapeutic vibrations are delivered to drive the intrinsic frequency towards a desired value. The device and methods more closely emulate natural physiologic feedback mechanisms and can reduce undesired side effects of other known therapies. The device can include a small and efficient electrical motor which is interconnected with a crank and link mechanism to generate oscillatory motion which is conducted to a flexible wall of a bio-compatible housing of the device.

Abstract: An exemplary method includes use of a multielectrode device that can help position a cardiac stimulation lead to an optimal site in the heart based at least in part on cardiac motion information acquired via the multielectrode device and one or more pairs of current delivery electrodes that establish potential fields (e.g., for use as a coordinate system). An exemplary multielectrode device may be a multielectrode catheter or a multifilar, electrode-bearing guidewire. Various other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: An exemplary method includes selecting a cross-correlation frequency having an associated cross-correlation period, detecting and binning a heart rate in a heart rate bin, detecting and binning an activity state in an activity state bin, repeating the detecting and binning a heart rate and the detecting and binning an activity state during a cross-correlation period, and summing the products a bin count of the heart rate bins and a bin count of the activity state bins to provide a cross-correlation index for the cross-correlation period. Other exemplary algorithms, 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 for reducing orthostatic hypotension are described. One technique detects an incident of orthostatic hypotension in a patient, and in response, increases cardiac stroke volume, at least in part, by stimulating the patient's phrenic nerve.

Abstract: Briefly, values representative of ventricular end-diastolic volume (EDV) are detected using ventricular electrodes and then heart failure, if occurring within the patient, is evaluated based on ventricular EDV. In this manner, ventricular EDV is used as a proxy for ventricular end-diastolic pressure. By using ventricular EDV instead of ventricular end-diastolic pressure, heart failure is detected and evaluated without requiring sophisticated sensors or complex algorithms. Instead, ventricular EDV is easily and reliably measured using impedance signals sensed by implanted ventricular pacing/sensing electrodes. The severity of heart failure is also evaluated based on ventricular EDV values and heart failure progression is tracked based on changes, if any, in ventricular EDV values over time.

Abstract: Techniques are provided for use by an implantable medical device for determining optimal or preferred atrioventricular (AV) pacing delay values for use in pacing the heart. Briefly, the atria and ventricles are paced using an initial AV pacing delay set to a value less than an intrinsic AV conduction delay so that intrinsic ventricular depolarizations are avoided. An internal electrical cardiac signal is sensed and atrial evoked responses and subsequent ventricular evoked responses are identified therein. Time delays between the atrial and ventricular evoked responses are measured and then a preferred or optimal AV pacing delay value is determined based on: the initial AV pacing delay; the measured time delays between the atrial and ventricular evoked responses; and on a predetermined preferred time delay to be achieved between atrial and ventricular evoked responses. Similar procedures are employed in connection with atrial sensed events. A calibration procedure is also described.

Abstract: Heart rate information is used at least in part to obtain one or more parameters for inducing respiration. In various implementations, respiratory parameters, such as a target breathing rate or a target tidal volume may be delivered by an implantable device to a patient during periods of altered respiration, such as sleep apnea or exercise. A respiratory parameter may also be obtained from a physiological variable, a patient's physical activity level, or metabolic demands.