Abstract: A system and method are provided for determining an index of autonomic nervous system (ANS) or sympathetic nervous system (SNS) activity for use in patient monitoring or therapy delivery control. An ANS or SNS index is calculated as a function of multiple monitored physiological variables that strongly correlate to changes in autonomic or sympathetic tone. These ANS-influenced variables are derived from selected hemodynamic and/or electrical signals and may include variables relating to any of: the maximum rate of pressure rise (dP/dtmax), the maximum rate of pressure decline (dP/dtmin), pulse pressure (PP), pre-ejection time interval (PEI) and/or systolic time interval (STI), heart rate (HR), heart rate variability (HRV), and baro-reflex gain. Changes in the ANS or SNS index may be used to automatically adjust a device delivered therapy.

Abstract: A blood flow rate sensor has at least one transmitter for emitting waves into a blood vessel, the propagation of which is deflected by cellular blood components, and at least two receiver units for receiving waves emitted by the transmitter. The receiver units are spaced from each other in the direction of blood flow, and are situated such that each receives waves from a different path through the blood. The output signal of each receiver unit is filtered or otherwise processed to obtain a noise component, and the noise components from the receiver units are cross-correlated to determine a time offset between the output signals. The time offset is inversely proportional to the blood flow rate.

Abstract: A system and method for managing preload reserve and tracking the inotropic state of a patient's heart. The S1 heart sound is measured as a proxy for direct measurement of stroke volume. The S3 heart sound may be measured as a proxy for direct measurement of preload level. The S1-S3 pair yield a point on a Frank Starling type of curve, and reveal information regarding the patient's ventricular operating point and inotropic state. As an alternative, or in addition to, measurement of the S3 heart sound, the S4 heart sound may be measured or a direct pressure measurement may be made for the sake of determining the patient's preload level. The aforementioned measurements may be made by a cardiac rhythm management device, such as a pacemaker or implantable defibrillator.

Abstract: Systems and methods using a heart valve and an implantable medical device, such as for event detection and optimization of cardiac output. The cardiac management system includes a heart valve, having a physiological sensor. The physiological sensor is adapted to measure at least one of an intrinsic electrical cardiac parameter, a hemodynamic parameter or the like. The system further includes an implantable electronics unit, such as a cardiac rhythm management unit, coupled to the physiological sensor of the heart valve to receive physiological information. The electronics unit is adapted to use the received physiological information to control delivery of an electrical output to the subject.

Abstract: The presence of a cardiac pulse in a patient is determined by evaluating physiological signals in the patient. In one embodiment, a medical device evaluates two or more different physiological signals, such as phonocardiogram (PCG) signals, electrocardiogram (ECG) signals, patient impedance signals, piezoelectric signals, and accelerometer signals for features indicative of the presence of a cardiac pulse. Using these features, the medical device determines whether a cardiac pulse is present in the patient. The medical device may also be configured to report whether the patient is in a VF, VT, asystole, or PEA condition, in addition to being in a pulseless condition, and prompt different therapies, such as chest compressions, rescue breathing, defibrillation, and PEA-specific electrotherapy, depending on the analysis of the physiological signals. Auto-capture of a cardiac pulse using pacing stimuli is further provided.

Abstract: A cardiac rhythm management (CRM) system includes an implantable medical device that senses a wireless electrocardiogram (ECG), which is a signal sensed with implantable electrodes and approximating a surface ECG. In one embodiment, the wireless ECG is sensed as a substitute signal for the intracardiac electrogram when the sensing of the intracardiac electrogram becomes unreliable.

Abstract: In an embodiment, the invention includes an implantable medical device with a pulse generator and a chemical sensor in communication with the pulse generator, the chemical sensor configured to detect an ion concentration in a bodily fluid. In an embodiment, the invention includes a method for providing cardiac arrhythmia therapy to a patient including sensing a physiological concentration of an analyte, communicating data regarding the physiological concentration of the analyte to an implanted pulse generator, and delivering therapy to the patient based in part on the physiological concentration of the ion. In an embodiment, the invention includes a method for monitoring diuretic therapy. In an embodiment, the invention includes a method for controlling delivery of an active agent into a human body. Other aspects and embodiments are provided herein.

Abstract: The disclosure relates to a method and system for obtaining baseline patient information. In some examples, a method may include acquiring first patient data, wherein the first patient data comprises at least one of first posture state data indicative of a plurality of posture states of a patient during a first time period or first therapy adjustment data indicative of a plurality of patient therapy adjustments made during the first time period; generating baseline patient information based at least in part on the first patient data; and comparing the baseline patient information to patient information generated based on second patient data. Therapy is not delivered to the patient according to a detected posture state of the patient during the first time period, and therapy is delivered to the patient according to the detected posture state of the patient during the second time period.

Abstract: The disclosure herein relates generally to methods for treating heart conditions using vagal stimulation, and further to systems and devices for performing such treatment. Such methods may include monitoring physiological parameters of a patient, detecting cardiac conditions, and delivering vagal stimulation (e.g., electrical stimulation to the vagus nerve or neurons having parasympathetic function) to the patient to treat the detected cardiac conditions.

Abstract: The disclosure herein relates generally to methods for treating heart conditions using vagal stimulation, and further to systems and devices for performing such treatment. Such methods may include monitoring physiological parameters of a patient, detecting cardiac conditions, and delivering vagal stimulation (e.g., electrical stimulation to the vagus nerve or neurons having parasympathetic function) to the patient to treat the detected cardiac conditions.

Abstract: An assembly includes an implantable medical device (IMD) including a conductive housing, and a fixation element assembly attached to the IMD. The fixation element assembly includes a set of active fixation tines and an insulator to electrically isolate the set of active fixation tines from the conductive housing of the implantable medical device. The active fixation tines in the set are deployable from a spring-loaded position in which distal ends of the active fixation tines point away from the implantable medical device to a hooked position in which the active fixation tines bend back towards the implantable medical device. The active fixation tines are configured to secure the implantable medical device to a patient tissue when deployed while the distal ends of the active fixation tines are positioned adjacent to the patient tissue.

Abstract: An active implantable medical device with atrial pacing for the treatment of diastolic heart failure. This device comprises circuits and leads for collecting right and left atrial events (16,18) and pacing the left atrium (18) and a sensor detecting myocardium contractions, preferably an endocardial acceleration sensor (20), delivering a signal representative of the myocardium contractions. Analysis of the signal allows a determination of the presence or absence of a detectable left atrial contraction distinguishable from the ventricular contraction. An interatrial delay is applied between the collection of a right atrial depolarization and the delivery of a left atrial pacing pulse. In the absence of left atrial contraction, the interatrial delay is iteratively reduced in successive cardiac cycles from an initial value to an adjustment value ensuring that a left atrial contraction appears, and then so maintained while the presence of a left atrial contraction continues.

Abstract: Apparatus for diastole trimming including a controller for producing a diastole ending signal, and one or more leads connected to the controller, for carrying the signal to lead connections to a heart, characterized by the controller detecting when a left ventricle (LV) of the heart is mostly full, and producing the diastole ending signal such that the diastole duration is trimmed. Apparatus for diastole trimming including a controller for producing a diastole ending signal, and a connection to a pacemaker, characterized by the controller having decision rules for indicating to the pacemaker when to fire and end the diastole. A method of programming a pacemaker characterized by increasing cardiac output by trimming duration of diastole. A method for increasing cardiac output including producing a signal to trim diastole duration, thereby increasing heart rate (HR) and increasing a product of stroke volume (SV) times HR. Related apparatus and methods are also described.

Abstract: An embodiment of a baroreflex stimulator comprises a pulse generator to provide a baroreflex stimulation signal through an electrode, and a modulator to modulate the baroreflex stimulation signal based on a circadian rhythm template. According to an embodiment of a method for operating an implantable medical device, comprising a baroreflex stimulation therapy is applied at a stimulation intensity using a baroreflex stimulator in the implantable medical device, and the baroreflex stimulation therapy is modulated based on a circadian rhythm template stored within the implantable medical device. Modulating the baroreflex stimulation therapy includes using the circadian rhythm template to change the stimulation intensity to mimic natural blood pressure fluctuations during the day.

Abstract: A system and method for correlating health related data for display. The system includes a medical device recording data and a display producing device which correlates the data and simultaneously displays different types of data or displays two sets of the same type of data along with the circumstances at which the two sets of data were recorded. Such displays aid a physician in prescribing and ascertaining the efficacy of cardiac therapies.

Abstract: An inspiratory muscle stimulation system uses an implantable medical device to deliver stimulation to control diaphragmatic contractions for slower and deeper breathing, thereby conditioning and strengthening inspiratory muscles. In various embodiments, respiratory and/or cardiac performance are monitored for controlling parameters of the stimulation.

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 apparatus for treating a heart of a patient includes a first lead and at least a second lead for pacing the heart adapted to be in electrical communication with the heart. The apparatus includes a microcontroller in communication with the first and second leads which triggers the first lead at either different times or the same time from when the microcontroller triggers the second lead. Alternatively, the apparatus includes a microcontroller in communication with the first and second leads that determines heart volume, including stroke volume, end-systolic volume, and calculated values including ejection fraction, from admittance from signals from the first and second leads and uses the admittance as feedback to control heart volume ejected, as measured by stroke volume, calculated values such as ejection fraction, and control end-systolic volume, with respect to the first and second leads. A method for treating the heart of a patient.

Abstract: An implantable cardiac device is configured and programmed to assess a patient's cardiopulmonary function by evaluating the patient's minute ventilation response. Such evaluation may be performed by computing a minute ventilation response slope, defined as the ratio of an incremental change in minute ventilation to an incremental change in measured activity level. The minute ventilation response slope may then be compared with a normal range to assess the patient's functional status.

Abstract: The present invention monitors and interprets physiological signals and spontaneous breathing events to detect the onset of arousal. Once the onset of arousal is determined, the present invention determines adjustments that are needed in the operation of a therapeutic device to avoid or minimize arousals. In one embodiment, the present invention includes one or more sensors which detect a patient's physiological parameters, a controller which monitors and determines the onset of arousal based on the physiological variables received from the sensor, and a therapeutic treatment device which is controlled by the controller. The sensor can be a combination of one or more devices which are able to monitor a physiological parameter that is used by the present invention to determine the onset of arousal or the onset of a sleep disorder. The sensors can be integrated into one unit or may operate independent of the others.

Abstract: Cardiac anodal electrostimulation detection systems and methods are described, such as for distinguishing between cathodal-only capture and at least partially anodal capture (e.g., combined anodal and cathodal capture, or between two anodes of which only one captures nearby cardiac tissue, etc.).

Abstract: An aspect of the present subject relates to an implantable medical system. An embodiment of the system includes a baroreflex stimulator, a myocardial infarction detector, and a controller. The baroreflex stimulator applies a baroreflex stimulation signal through an electrode. The myocardial infarction detector detects an event indicative of myocardial infarction, The controller is connected to the baroreflex stimulator and to the myocardial infarction detector, and is adapted to apply a baroreflex therapy in response to a detected event indicative of myocardial infarction. Other aspects are provided herein.

Abstract: Various system embodiments comprise a neural stimulation delivery system adapted to deliver a neural stimulation signal for use in delivering a neural stimulation therapy, a side effect detector, and a controller. The controller is adapted to control the neural stimulation delivery system, receive a signal indicative of detected side effect, determine whether the detected side enact is attributable to delivered neural stimulation therapy, and automatically titrate the neural stimulation therapy to abate the side effect. In various embodiments, the side effect detector includes a cough detector. In various embodiments, the controller is adapted to independently adjusting at least one stimulation parameter for at least one phase in the biphasic waveform as part of a process to titrate the neural stimulation therapy. Other aspects and embodiments are provided herein.

Abstract: A method and system for use in selecting a cardiac pacing site includes sensors for tracking wall motion (e.g., sensors coupled to the right and left ventricular heart wall). The wall motion of one or more non-paced cardiac cycles is compared to the wall motion of one or more paced cardiac cycles to determine the effectiveness of one or more pacing sites. For example, image data may be generated to notify the user as to the effectiveness of the one or more pacing sites.

Abstract: An exemplary method includes delivering a cardiac resynchronization therapy using an atrio-ventricular delay and an interventricular delay, monitoring patient activity, optimizing the atrio-ventricular delay and the interventricular delay for a plurality of patient activity states to generate a plurality of optimal atrio-ventricular delays and a plurality of optimal interventricular delays, storing the optimal atrio-ventricular delays and the optimal interventricular delays in association with corresponding patient activity states, detecting a change in patient activity, adjusting an atrial pacing rate in response to the detected change in patient activity based at least in part on a heart failure status and setting the atrio-ventricular delay and the interventricular delay, in response to the detected change in patient activity, using a stored optimal atrio-ventricular delay that corresponds to the patient activity and a stored optimal interventricular delay that corresponds to the patient activity.

Abstract: Systems and methods are provided for use by an implantable medical device capable of automatically adjusting the sensitivity with which electrical cardiac signals are sensed within a patient, i.e. a device equipped with Automatic Sensitivity Control (ASC.) In a first example, ASC parameters are automatically adjusted by the device itself based on parameters derived from both R-waves and T-waves and further based on a detected noise floor. In a second example, a profile representative of the shape of cardiac signals is generated by the device. ASC parameters are then adjusted based on the profile. In various embodiments, histograms are used to determine sizes and shapes of the R-waves and T-waves via statistical prevalence techniques. The histograms are also employed to derive the aforementioned profile.

Abstract: An implantable medical device for monitoring tissue perfusion that includes a light source emitting light having a light wavelength corresponding to a blue to ultraviolet light spectrum and a light detector receiving light emitted by the light source and scattered by a volume of body tissue. The light detector emits a signal correlated to the received light wavelength, and a processor receives the signal from the light detector and determines a patient condition in response to the signal.

Abstract: A method and device for treating epilepsy are disclosed which provide for electrical, chemical or magnetic stimulation of certain areas of the brain to modulate neuronal activity of areas associated with symptoms of epilepsy. Deep brain stimulation is combined with vagus nerve stimulation to enhance symptomatic relief of the disorder. Some embodiments also employ a sensing capability to optimize the therapeutic treatment regimen.

Abstract: A method to optimize CRT therapy using ventricular lead motion analysis, either radiographically or with three dimensional electromagnetic mapping, to determine whether focal dyssynchrony is present at baseline, and whether biventricular pacing improves synchronicity and fractional shortening, and if no improvement is evidenced, changing the timing offset, pacing configuration and/or repositioning the ventricular leads to optimize effectiveness of CRT therapy. Various uses of this method include: diagnostic, with temporary leads to determine presence or absence of dyssynchrony and response to pacing; and therapeutic, to guide lead placement and programming during implant of CRT, and to optimize reprogramming of CRT during follow-up.

Abstract: A system and method for optimizing cardiac resynchronization therapy and visualizing cardiac pacing intervals. The system comprises at least one hemodynamic sensor; at least one electrode; a learning module; a micro controller; and at least one graphical interface for showing at least one of a PRV vs. PLV diagram and a responder curve.

Abstract: An implantable heart monitoring system has a control circuit that operates an implanted vibrator to emit a vibration signal that interacts with tissue in vivo. A vibration sensor detects vibrations after interaction with the tissue, and supplies a detection signal to the control circuit. The control circuit analyzes the vibrations in the detected signal relative to the vibration signal, and derives information concerning at least one mechanical property of the heart therefrom, such as stiffness and/or thickness of at least a part of the heart.

Abstract: A method for detecting a condition of a heart of a patient using an implantable medical device, including the steps of sensing acoustic signals indicative of heart sounds of the heart of the patient; extracting signals corresponding to a first heart sound (S1) and a second heart sound (S2) from sensed signals; calculating an energy value corresponding to a signal corresponding to the first heart sound (S1) and an energy value corresponding to the second heart sound (S2); calculating a relation between the energy value corresponding to the first heart sound and the energy value corresponding to the second heart sound for successive cardiac cycles; and using at least one relation to detect the condition or a change of the condition. A medical device for determining the posture of a patient and a computer readable medium encoded with instructions are used to perform the inventive method.

Abstract: Electrical noise may be discriminated from sensed heart signals based on cardiovascular pressure. A plurality of detected cardiovascular pressure values are respectively associated with a plurality of detected tachyarrhythmia events. In some examples, a variance in the cardiovascular pressure, e.g., above a threshold range, may indicate that the detected tachyarrhythmia events are at least partially attributable to electrical noise. In some examples, stimulation therapy to a heart of a patient may be controlled based on the detection of a tachyarrhythmia episode and a variability in the cardiovascular pressure values that are associated with the tachyarrhythmia episode. In other examples, a sensing integrity indication may be generated upon determining that a tachyarrhythmia episode was associated with a variable cardiovascular pressure.

Abstract: A first chamber minute ventilation rate is determined based on a first transthoracic impedance signal received from a first chamber of a heart and a second chamber minute ventilation rate is determined based on a second transthoracic impedance signal received from a second chamber of the heart. A processor compares the minute ventilation rates to determine a rate. In one embodiment, an accelerometer sensor provides data for evaluating propriety of a rate. Before implementing a rate change, signals from multiple sensors are cross-checked.

Abstract: A cardiac rhythm management device is configured to deliver pre-excitation pacing to one or more sites in proximity to an infarcted region of the ventricular myocardium. The pre-excitation pacing in conjunction with counterpulsation therapy serves to either prevent or minimize post-infarct remodeling.

Abstract: Methods for evaluating motion of a cardiac tissue location, e.g., heart wall, are provided. In the subject methods, timing of a signal obtain from a strain gauge stably associated with the tissue location of interest is employed to evaluate movement of the cardiac tissue location. Also provided are systems, devices and related compositions for practicing the subject methods. The subject methods and devices find use in a variety of different applications, including cardiac resynchronization therapy.

Abstract: An apparatus for reversing ventricular remodeling with electro-stimulatory therapy. A ventricle is paced by delivering one or more stimulatory pulses in a manner such that a stressed region of the myocardium is pre-excited relative to other regions in order to subject the stressed region to a lessened preload and afterload during systole. The unloading of the stressed myocardium over time effects reversal of undesirable ventricular remodeling.

Abstract: A medical device includes a preload determination unit for determining the preload of a ventricle for a cardiac cycle and providing a preload value representing the preload; a contractility determination unit for determining the contractility of the ventricle for the cardiac cycle and providing a contractility value representing the contractility; and an evaluation unit connected to the preload determination unit and the contractility determination unit, with the evaluation unit being configured to evaluate contractility values versus associated preload values.

Abstract: A system and method determining physiological status of a patient. A determination is made whether the patient is sleeping. The amplitude and change in voltage over time of any intramyocardial electrogram is measured for a right ventricle and a left ventricle of a heart of the patient for a predefined number of heartbeats at a specified time interval in response to determining the patient is asleep. The measurements are averaged for the right ventricle and left ventricle. The averaged measurements are transmitted to a receiver for communication to an intended recipient.

Abstract: The presence of a cardiac pulse in a patient is determined by evaluating physiological signals in the patient. In one embodiment, a medical device evaluates two or more different physiological signals, such as phonocardiogram (PCG) signals, electrocardiogram (ECG) signals, patient impedance signals, piezoelectric signals, and accelerometer signals for features indicative of the presence of a cardiac pulse. Using these features, the medical device determines whether a cardiac pulse is present in the patient. The medical device may also be configured to report whether the patient is in a VF, VT, asystole, or PEA condition, in addition to being in a pulseless condition, and prompt different therapies, such as chest compressions, rescue breathing, defibrillation, and PEA-specific electrotherapy, depending on the analysis of the physiological signals. Auto-capture of a cardiac pulse using pacing stimuli is further provided.

Abstract: An exemplary includes acquiring an electroneurogram of the right carotid sinus nerve or the left carotid sinus nerve, analyzing the electroneurogram for at least one of chemosensory information and barosensory information and calling for one or more therapeutic actions based at least in part on the analyzing. Therapeutic actions may aim to treat conditions such as sleep apnea, an increase in metabolic demand, hypoglycemia, hypertension, renal failure, and congestive heart failure. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: A method and apparatus for treating or preventing neurocardiogenic syncope is disclosed. Upon detection of bradycardia or a drop in blood pressure indicating the onset of syncope, electrostimulation pulses are delivered during the heart's refractory period. The pulses are non-excitatory but increase myocardial contractility and thereby increase cardiac output.

Abstract: A method and apparatus for verifying a determined cardiac event in a medical device based on detected variation in hemodynamic status that includes a plurality of sensors sensing cardiac signals, and a physiologic sensor sensing physiologic signals to generate a plurality of variation index samples corresponding to the sensed signals. A microprocessor detects a cardiac event in response to the sensed cardiac signals, computes a variation index trend associated with a predetermined number of variation index samples of the plurality of variation index samples, determines whether the sensed cardiac signals are associated with noise in response to the computed variation index, and confirms the determined cardiac event in response to the sensed cardiac signals not being associated with noise.

Abstract: A device comprises a cardiac contraction sensing circuit, a timer circuit, an electrical stimulation circuit, and a controller. The timer circuit provides a time duration of an atrial-atrial interval between successive atrial contractions, a ventricular-ventricular interval between successive ventricular contractions, and an atrial-ventricular (A-V) interval between an atrial contraction and a same cardiac cycle ventricular contraction. The controller includes an event detection module and a pacing module. The event detection module is configured for determining whether A-V block events are sustained over multiple cardiac cycles. The pacing module is configured for providing pacing therapy according to a primary pacing mode that includes AAI(R) mode with non-tracking VVI backup mode, and for switching the pacing therapy to a secondary tracking pacing mode if A-V block events are sustained over multiple cardiac cycles.

Abstract: Systems and methods to monitor cardiac function using information indicative of lead motion are described. In an example, a system including an implantable medical device can include a receiver circuit configured to be electrically coupled to conductor comprising a portion of an implantable lead and be configured to obtain information indicative of a movement of the implantable lead due at least in part to a motion of a heart. The system can include a sensing circuit configured to obtain information indicative of cardiac electrical activity. The system can include a processor circuit configured to construct a template representative of a contraction of the heart, where the template can be constructed using the information indicative of the movement of the implantable lead due at least in part to the motion of the heart during the contraction, and using the information indicative of the cardiac electrical activity sensed during the contraction.

Abstract: An implantable pacing device for delivering ventricular pacing may be configured to intermittently reduce the AVD interval for beneficial effect in patients with compromised ventricular function (e.g., HF patients and post-MI patients). The AVD interval may be reduced in an AVD reduction mode, by shortening the AVD in an atrial triggered ventricular pacing mode or by switching to a non-atrial triggered ventricular pacing mode (e.g., VVI) and delivering paces at a rate above the intrinsic rate. The physiological effects of AVD reduction may be either positive or negative on cardiac output, depending upon the individual patient.

Abstract: A first lead provides therapeutic stimulation to the heart and includes a first mechanical sensor that measures physical contraction and relaxation of the heart. A controller induces delivery of therapeutic stimulation via the first lead. The controller receives signals from the first mechanical sensor indicative of the contraction and relaxation; develops a template signal that corresponds to the contraction and relaxation; and uses the template signal to modify the delivery of therapeutic stimulations. In another arrangement, a second lead, with a second mechanical sensor also provides signals to the controller indicative of contraction and relaxation. The first mechanical sensor is adapted to be positioned at the interventricular septal region of the heart, and the second mechanical sensor is adapted to be positioned in the lateral region of the left ventricle. The controller processes the signals from the first mechanical sensor and the second mechanical sensor to develop a dysynchrony index.

Abstract: A method of providing cardiac stimulation therapy and a device for providing the therapy. A patient's cardiac activity as well as cyclical respiration is monitored. Cardiac stimulation is provided as indicated as therapeutic intervention for a variety of cardiac arrhythmias according to variable timing parameters. One or more of the timing parameters under which cardiac pacing stimulations are provided is varied or modulated with the cyclical variations in respiration. The one or more timing parameters are generally shortened or elongated in concert with the alternating inspiration/exhalation phases of respiration. In certain implementations, the patient's respiration is inferred from cardiac based physiologic signals. The methods and devices for providing cardiac stimulation therapy more accurately emulate natural healthy physiologic activity.

Abstract: Various system embodiments comprise a stimulator adapted to deliver a stimulation signal for a heart failure therapy, a number of sensors adapted to provide at least a first measurement of a heart failure status and a second measurement of the heart failure status, and a controller. The controller is connected to the stimulator and to the number of sensors. The controller is adapted to use the first and second measurements to create a heart failure status index, and control the stimulator to modulate the signal using the index. Other aspects and embodiments are provided herein.

Abstract: An implantable heart stimulating device has a stimulation pulse generator that emits stimulation pulses at an adjustable stimulation rate, an activity sensor that emits an activity signal in response to detected activity of the patient, and a physiological parameter sensor that generates a physiological sensor signal in response to a detected physiological parameter. The activity and physiological sensor signals are supplied to a control arrangement that sets the stimulation rate for the stimulation pulse generator by executing a stimulation rate algorithm dependent on those signals. In the stimulation rate algorithm, if the physiological signal indicates an emotional stress on the part of the patient, the stimulation rate is increased to an adjustable emotional stress rate level, and if no increase in the activity signal occurs during a predetermined time period following the stimulation rate increase, the stimulation rate is decreased.