Abstract: Techniques are provided for tracking patient respiration based upon intracardiac electrogram signals or other electrical cardiac signals. Briefly, respiration patterns are detected by integrating cardiac electrical signals corresponding to individual paced cardiac cycles. The integrals may be obtained between consecutive pairs of ventricular pacing pulses or between consecutive pairs of atrial pacing pulses. In either case, cyclical changes in the integrals of the individual cardiac cycles are tracked. The cyclical changes are representative of respiration. Once respiration patterns have been identified, episodes of abnormal respiration, such as apnea, hyperpnea, nocturnal asthma, or the like, may be detected and therapy automatically delivered.

Abstract: An active medical device that is able to detect and treat ventiliatory activity disorders during sleep. This device measures the patient's respiratory activity, delivers a signal of the ventiliatory activity of the patient, analyzes the ventiliatory activity signal, and detects the occurrence of hypopneas. The analysis includes calculating at regular intervals a sliding average of the signal of ventiliatory activity, comparing the values of the successive sliding averages thus calculated, and detecting an occurrence of an hypopnea when, for two successive sliding averages, the difference between the averages crosses a predetermined threshold of comparison. When the device is one that also delivers cardiac stimulation pulses, it is advantageously envisaged to modify an operating parameter, in particular the stimulation rate based on the detected hypopnea, to treat the hypopnea.

Abstract: Techniques are provided for tracking patient respiration based upon intracardiac electrogram (IEGM) signals or other electrical cardiac signals. Briefly, respiration patterns are detected based upon cycle-to-cycle changes in morphological features associated with individual electrical events with the IEGM signals. For example, slight changes in the peak amplitudes of QRS-complexes, P-waves or T-waves are tracked to identify cyclical variations representative of patient respiration. Alternatively, the integrals of the morphological features of the individual events may be calculated for use in tracking respiration. In any case, once respiration patterns have been identified, episodes of abnormal respiration, such as apnea, hyperpnea, nocturnal asthma, or the like, may be detected and therapy automatically delivered. In particular, techniques for detecting abnormal respiration based on various respiratory parameters derived from the IEGM—such as respiration depth and respiration power—are described.

Abstract: Heart treatment equipment and a heart treatment method directed to prevention of a fatal arrhythmia by detecting a physical exercise or a mental stress by using a sensor and thereafter controlling the vagus nerve stimulation, wherein sensor means for detecting various living body information for generating a signal which designates degree of a sympathetic tone is provided and heart rate threshold for carrying out the vagus nerve stimulation is adjusted according to the living body information detected by the sensor means. Further, a nerve stimulation parameter for adjusting the strength of the vagus nerve stimulation is adjusted in response to the degree of the patient sympathetic tone.

Abstract: Methods and systems involve adjusting cardiac pacing based on information acquired via a respiratory therapy device. A medical system includes a respiratory therapy device having one or more sensors and a therapy delivery unit. The one or more sensors are configured to sense respiration cycles. The therapy delivery unit is configured to deliver an external respiratory therapy to the patient. The medical system also includes a pulse generator configured to deliver cardiac pacing pulses to the patient. A controller is coupled to the one or more sensors and the pulse generator. The control unit configured to adjust a cardiac pacing rate based on the patient's respiration cycles.

Abstract: A cardiac rhythm management device in which an accelerometer is used to detect diaphragmatic or other skeletal muscle contraction associated with the output of a pacing pulse. Upon detection of diaphragmatic contraction, the device may be configured to automatically adjust the pacing pulse energy and/or pacing configuration.

Abstract: A system comprising an implantable medical device (IMD). The IMD comprises a ventricular heart signal sensing circuit to provide a ventricular heart signal, at least one sensor operable to provide an electrical signal representative of patient activity, a sensor interface circuit coupled to the at least one sensor to provide an activity signal, and a controller circuit coupled to the heart signal sensing circuit and the sensor interface circuit. The controller circuit is operable to determine whether ventricular ectopy occurs during recovery from exercise using the heart signal, and to set at least one warning indicator if ventricular ectopy occurs during the recovery from exercise.

Abstract: An implantable cardiac stimulation device treats apnea with either phrenic nerve stimulation pulses or cardiac stimulation pulses. The device includes an apnea detector that detects apnea of a patient, a blood oxygen saturation monitor that measures a blood oxygen saturation level of the patient responsive to detection of apnea, and a tiered therapy circuit that provides phrenic nerve stimulation pulses if the measured blood oxygen saturation level is within a first range and cardiac stimulation pulses if the measured blood oxygen saturation level is within a second range. The cardiac stimulation pulses are preferably provided in a DAO pacing mode.

Abstract: An implantable medical device includes a dual-use sensor such as a single accelerometer that senses an acceleration signal. A sensor processing circuit processes the acceleration signal to produce an activity level signal and a heart sound signal. The implantable medical device provides for rate responsive pacing in which at least one pacing parameter, such as the pacing interval, is dynamically adjusted based on the physical activity level. The implantable medical device also uses the heart sounds for pacing control purposes or transmits a heart sound signal to an external system for pacing control and/or diagnostic purposes.

Abstract: A method of setting or adjusting a cardiac pacemaker in a patient diagnosed with cardiac asynchrony, which method comprises the steps of: i) implanting cardiac pacing wires into at least the right ventricle and the left ventricle of the heart of the patient, ii) continuously monitoring and recording the cardiac output, nominal stroke volume and/or arterial pressure of the patient on a beat-by-beat basis, iii) continuously monitoring and recording the respiratory cycle of the patient, and iv) adjusting the conduction delay between the electronic impulses to the cardiac pacing wires until a synchronization of respiratory changes with changes in the cardiac output, stroke volume or arterial pressure of the patient is obtained.

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.

Abstract: A method of data management for optimizing the patient outcome from the provision of cardiac resynchronization therapy (CRT) is described. This method describes a process by which sets of dynamic cardiopulmonary dependent variables are measured during steady-state conditions, displayed, and translated into quantitative and qualitative measurements while the independent variables of CRT, device lead placement and atrial-ventricular and interventricular delay settings of bi-ventricular pacemaker systems, are altered by a physician. In combination with visual observation and computer-assisted ranking of the dependent variables, a physician can utilize the resulting information to render decisions on the optimal choice of the independent variables.

Abstract: An ICD processing system for acquiring breathing pattern signals from intracardiac electrograms obtained from implantable cardiac devices. The system may include both an implantable ICD device and an external processing system. Both the ICD module and the external processing system processing data to generate a representation for the respiration rate for a patient using intracardiac electrogram data obtained by the ICD device. The ICD module and the external processing module communicate with each other to pass collected patient data from the ICD module to the external processing system. The ICD module and the external processing module process the electrogram data to obtain an processed data representation of the respiration data which is used to estimate the respiration rate.

Abstract: A cardiac stimulation device and method monitor and store discrepancies in sensor indicated rates determined from two or more sensors generating signals related to metabolic demand. One feature included in the present invention is a sensor cross-check record that stores the time, duration and sensor indicated rates whenever individual sensor indicated rates differ by more than a discrepancy threshold. This record allows a clinician to monitor an abnormal patient condition or determine if a sensor is not functioning properly or is programmed sub-optimally. Another feature provided by the present invention is a sensor cross-check histogram in which sensor indicated rate differences are stored. Histogram data aids the clinician in selecting programmable operating parameters that control the calculation of sensor indicated rates and the rate response of the cardiac stimulation device.

Abstract: An implantable medical device delivers augmentation therapy to intervene in a pattern of sleep-disordered breathing. Augmentation therapy includes the delivery of electrical stimulation to cardiac tissue above and/or below a capture threshold. PESP and NES/CCM are possible augmentation therapies that are used alone or in combination. In addition, augmentation therapies can be used with other pacing therapies such as atrial overdrive pacing and atrial coordinated pacing as a therapy for sleep-disordered breathing.

Abstract: A method and an apparatus for performing rate responsive control in an implantable medical device using a scaling factor. Sensor data is acquired using a sensor operatively coupled with the implantable medical device. At least one setpoint for controlling a rate of therapy is generated, the setpoint being based upon the sensor data. A scaling factor adjustment process is performed for scaling the internal sensor data to correlate the sensor data to the setpoint. The rate of therapy is adjusted based upon the scaling factor adjustment.

Abstract: A method and system for operating a rate-adaptive pacemaker utilizing minute ventilation to measure exertion level. The method is applicable to heart failure patients who exhibit an oscillatory minute ventilation pattern.

Abstract: An implantable cardiac stimulation device comprises a metabolic demand sensor, an activity sensor, and one or more pulse generators. The metabolic demand sensor and activity sensor can sense metabolic demand and physical activity parameters, respectively. The pulse generators can generate cardiac pacing pulses with timing based on a comparison of the metabolic demand and physical activity parameters. The timed cardiac pacing pulses can prevent a sleep apnea condition.

Abstract: A cardiac rhythm management device includes a dual chamber pacemaker, especially designed for treating congestive heart failure. The device incorporates a program microcontroller which is operative to adjust the pacing site, AV delay and interventricular delay of the pacemaker so as to achieve optimum hemodynamic performance. Atrial cycle lengths measured during transient (immediate) time intervals following a change in the site, AV delay and interventricular delay are signal processed and a determination can then be made as to which particular configuration yields the optimum performance. Paced transient beats following periods of baseline beats are synchronized to the patient's respiratory cycle to minimize effects of respiratory noise on atrial cycle length measurements.

Abstract: An active medical device to diagnose a patient respiratory profile. This device is able to measure respiratory activity and deliver a signal (26) representative of the periodicity and amplitude of the successive respiratory cycles of the patient, in particular, a of minute ventilation (MV) signal. The device is able to analyze the aforementioned signal and discriminate between various types of respiratory profiles, in particular, to diagnose a respiratory profile of the Cheyne-Stokes type. This is achieved by detecting an alternation of respiratory cycles of hyperventilation (20) separated by periods of respiratory pause (22) or periods of hypoventilation or normal ventilation (24) and, in the latter case, to discriminate between periods of respiratory pause, corresponding to a profile of the Cheyne-Stokes (CSR) type, and periods of hypoventilation or normal ventilation, corresponding to a profile of the periodic breathing (PB) type.

Abstract: A cardiac rhythm management device in which an accelerometer is used to detect diaphragmatic or other skeletal muscle contraction associated with the output of a pacing pulse. Upon detection of diaphragmatic contraction, the device may be configured to automatically adjust the pacing pulse energy and/or pacing configuration.

Abstract: A ventilation system (1, 10) is combined with a measuring method (2, 22, 222) for electric impedance tomography (EIT). Bidirectional data exchange between the two systems is provided. Both the ventilation system (1, 10) and the measuring system (2, 22, 222) have a first and second communications electronic unit (11, 12) each with associated transmitting and receiving means for the bidirectional data exchange.

Abstract: An implantable cardiac device detects a progression or regression in heart disease such as congestive heart failure. An activity sensor and a respiration sensor generate raw signals indicative of the patient's activity level and respiration level. Degradation or improvement of the patient's activity and respiration over a predetermined time corresponds to an indication of the progression or regression of the heart disease. A processor coupled to the sensors is programmed to process the raw sensor signals over the predetermined time and stores the processed sensor signals in a memory having a data storage area. A telemetry circuit coupled to the memory is configured to transmit the stored sensor signals to an external monitor for subsequent display. The processor further controls pacing of the heart, adjusts pacing therapy responsive to the process signals, and process the raw respiration signals when the patient is in a number of different active states.

Abstract: An implantable medical device system is described including an implantable medical device for implantation in a patient. One embodiment of the implantable medical device includes a therapy component for providing a therapy to the patient, a minute ventilation (MV) sensing circuit producing MV values indicative of a MV of the patient at time intervals, and computational circuitry. The computational circuitry receives a number of the MV values over a period of time, calculates a statistical parameter (e.g., a mean) of the MV values, and calculates a deviation of the MV values from the statistical parameter (e.g., a standard deviation of the MV values). The computational circuitry detects an onset of sleep in the patient when the deviation of the MV values from the statistical parameter is less than a predetermined MV threshold value, and signals the therapy component to modify the therapy when the onset of sleep is detected in the patient.

Abstract: An active implantable medical device, in particular a pacemaker, cardioverter, defibrillator and/or a multisite device having circuits for measuring a trans-septal bio-impedance. This device is used with electrodes placed in a plurality of distinct respective sites comprising at least one left ventricular site and one right atrial site. These electrodes are connected to a collection circuit for collecting cardiac signals, in particular to detect a potential of depolarization, and to a stimulation circuit, to apply stimulation pulses to at least some of the aforementioned sites. The device evaluates the cardiac flow by obtaining an intracardiac measurement of the bio-impedance, more particularly measuring the trans-septum impedance bio-between the left ventricle and the right atrium, by injection of a current (16) between an atrial site (RA−) and a ventricular site (LV−), and collection of a differential potential (20) between an atrial site (RA+) and a ventricular site (LV−).

Abstract: Implantable heart-monitoring devices, such as defibrillators, pacemakers, and cardioverters, detect onset of abnormal heart rhythms and automatically apply corrective electrical therapy, specifically one or more bursts of electric charge, to abnormally beating hearts. Critical parts in these devices include the capacitors that store and deliver the bursts of electric charge. Some devices use cylindrical aluminum electrolytic capacitors which include terminal that extend from one end of the case, making the capacitor longer than it otherwise would be and generally necessitating use of larger implantable device housings. Accordingly, the inventors devised unique capacitor connection structures that allow size reduction. One exemplary capacitor includes two conductive endcaps at opposite ends of its capacitive element, instead of two upright terminals at one end, thereby allowing reduction in the height or volume of the capacitor and/or increases in the dimensions of other components, such as aluminum foils.

Abstract: The present invention relates to methods and apparatus for detection and treatment of syncope in an implantable medical device, and particularly to detection of syncope as a function of a predetermined increase in one or more respiration parameter and drop in heart rate and optionally delivering a pacing therapy in response thereto. The onset of a syncopal episode is declared when the patient's respiration rate and/or tidal volume and/or minute ventilation increases by a predetermined increment or threshold and a heart rate drops below a threshold heart rate drop. The threshold heart rate drop is preferably established as a function of the change in the respiration parameter.

Abstract: An active implantable medical device for electrostimulation in response to a determined sleep apnea syndrome, particularly a pacemaker. This device measures the respiratory activity of the patient, using for example, a minute ventilation sensor and/or a blood oxygen saturation sensor, and analyzes the sensor signal, to determine occurrence of an apnea according to the signal delivered by the sensor. The device also delivers an increase cardiiac pacing rate in the event of detection of apnea. The device also can deliver a neurological and/or cardiac stimulation so as to apply selectively to the patient an electric stimulus. The device also determines the patients's state of activity, according to predetermined criteria, such that the increased pacing rate is provided only during a sleep phase and otherwise inhibited.

Abstract: A leg tanning apparatus including a tanning module and a support module. The tanning module has a length that is on the order of a length of legs on a human body. The tanning module includes an outer shell and a plurality of tanning bulbs that are mounted in the outer shell. The plurality of bulbs are capable of emitting ultraviolet light. The support module maintains the tanning module at an acute angle.

Abstract: An active implantable medical device, in particular a pacemaker, defibrillator or cardioveter of the multisite type, including a circuit for measuring intercardiac impedance. Electrodes are placed in at least one ventricular site and one atrial site, and are connected to a circuit for the collection of cardiac signals, to detect a depolarization potential, as well as to a stimulation circuit, to apply stimulation pluses to at least some of the aforementioned sites. The measurement of a trans-pulmonary bio-impedance is obtained by injecting a current from an injection circuit (16) between the case (18) of the device and a first atrial (RA−) (or ventricular) site, and measuring a differential potential (20) between the case (18) and a point of measurement located in a second atrial (RA+) (or ventricular) site using a collection circuit.

Abstract: Methods of adjusting output mapping in response to historical signal input data relative to a reference value, and apparatus to perform the methods. The methods are suited for use in adjusting rate-adaptive pacemakers in response to a patient's demonstrated activity relative to a predetermined activity level. The methods include using historical physiologic sensor input to derive a patient's activity. The methods further include tuning a rate-adaptive curve in response to a demonstrated exertion level and a demonstrated exertion time indicative of a breadth and frequency of a patient's activity above some reference value. Pacemakers adapted to perform the methods include a processor, at least one physiologic sensor, a variable-rate pulse generator and a memory for storing historical physiologic sensor data.

Abstract: A portable iontoforesis device that can be used by everybody anytime anywhere. A freely-detachable medicine container, which supplies medicine to the first electrode, is mounted on the main body of the iontoforesis device. The liquid medicine flows from the medicine container into the passage formed in the first electrode. A pulse current is caused to flow between the first electrode and second electrode. The liquid medicine flowing through the passage infiltrates into the human skin by iontoforesis. The medicine-infiltratable soft material, being mounted to the first electrode in a freely-detachable manner, can contact the skin smoothly.

Abstract: A cardiac rhythm management (CRM) device detects transthoracic impedance, extracts ventilation or other information, and adjusts a delivery rate of the CRM therapy accordingly. A four-phase sequence of alternating direction current pulse stimuli is periodically delivered to a patient's thorax. A transthoracic impedance signal is extracted using a weighted demodulation. Signal processing extracts ventilation information and removes cardiac stroke information using an adaptive lowpass filter. The adaptive filter cutoff frequency is based on the patient's heart rate; a higher cutoff frequency is provided for higher heart rates. Peak/valley detection indicates tidal volume, which is integrated to extract minute ventilation (MV). Short and long term averages are formed and compared to establish a MV indicated rate. Rate adjustment ignores MV information when a noise-measurement exceeds a threshold.

Abstract: A method and apparatus for providing congestive heart failure therapy status. An electronic device, preferably a cardiac rhythm management device, capable of measuring transthoracic impedance and for sensing a level of physical activity is implanted in a patient. The transthoracic impedance signal is processed to obtain an estimate of the subject's minute ventilation, respiratory rate, tidal volume, inspiratory rate and expiratory rate. From accelerometer measured activity, an estimate is obtained of oxygen uptake, carbon dioxide production and work rate.

Abstract: An implantable cardiac device that is adapted to periodically measure a body parameter, such as transthoracic impedance, at time periods selected so that the body parameter is primarily indicative of the respiration of the patient. In this way, a ventilation parameter, such as minute ventilation, can be reconstructed from the signals without requiring filtering of the sampled signals. In one embodiment, the implantable cardiac device measures transthoracic impedance during each quiescent period of the heart and thereby obtains a plurality of transthoracic impedance data points which are then used to reconstruct a ventilation signal. As the transthoracic impedance data points are obtained during the quiescent period, the contribution of the heart to the resulting transthoracic impedance measurement can be ignored and the resulting measurements are indicative of the action of the heart.

Abstract: A method for automatically determining the ventilatory (or “anaerobic”) threshold breakpoint for adaptive rate pacing without the need for directly measuring anaerobic threshold or ventilatory threshold comprises: (a) positioning a first sensing electrode in the heart or superior vena cava of a patient carrying an implanted pacemaker, the first sensing electrode connected to the implanted pacemaker; (b) positioning a second sensing electrode in the thoracic region of the patient and spaced apart from the first sensing electrode; (c) determining the chest wall impedance of the patient between the first sensing electrode and the second sensing electrode; (d) measuring the ventilation (e.g., the minute ventilation) of the subject from the chest wall impedance during submaximal exercise by the patient; and then (e) determining the ventilatory threshold breakpoint of the patient from the measured ventilation.

Abstract: Methods and apparatus for automatic estimation of output mapping parameters for a control system where those output mapping parameters may be estimated from changes in sensor input data when the control system enters steady-state motion. Methods and apparatus for automatic estimation of minute ventilation at anaerobic threshold and minute ventilation at peak exercise for adjustment of rate-adaptive curves of pacemakers. The methods include detecting steady-state motion of the pacemaker and calculating minute ventilation at anaerobic threshold and minute ventilation at peak exercise from changes in minute ventilation sensor data corresponding to the period of steady-state motion.

Abstract: In a rate-responsive pacemaker, the metabolic demand of the patient is determined by measuring the patient's minute volume. Preferably, the pacemaker has a housing with a header, two external electrodes formed on the housing and/or the header, and at least one lead with a distal electrode extending from the header to the patient's heart. The minute volume is determined by injecting a test current pulse between one of the external electrodes and the distal electrode, and detecting the resulting voltage between the distal electrode and the second external electrode.

Abstract: An active implantable medical device, in particular a pacemaker, cardioverter, defibrillator and/or a multisite device having circuits for measuring a trans-septal bio-impedance. This device is used with electrodes placed in a plurality of distinct respective sites comprising at least one left ventricular site and one right atrial site. These electrodes are connected to a collection circuit for collecting cardiac signals, in particular to detect a potential of depolarization, and to a stimulation circuit, to apply stimulation pulses to at least some of the aforementioned sites. The device evaluates the cardiac flow by obtaining an intracardiac measurement of the bio-impedance, more particularly measuring the trans-septum impedance bio-between the left ventricle and the right atrium, by injection of a current (16) between an atrial site (RA−) and a ventricular site (LV−), and collection of a differential potential (20) between an atrial site (RA+) and a ventricular site (LV−).

Abstract: An active implantable medical device, in particular a pacemaker, defibrillator or cardioveter of the multisite type, including a circuit for measuring intercardiac impedance. Electrodes are placed in at least one ventricular site and one atrial site, and are connected to a circuit for the collection of cardiac signals, to detect a depolarization potential, as well as to a stimulation circuit, to apply stimulation pluses to at least some of the aforementioned sites. The measurement of a trans-pulmonary bio-impedance is obtained by injecting a current from an injection circuit (16) between the case (18) of the device and a first atrial (RA−) (or ventricular) site, and measuring a differential potential (20) between the case (18) and a point of measurement located in a second atrial (RA+) (or ventricular) site using a collection circuit.

Abstract: A method and apparatus for providing congestive heart failure therapy status. An electronic device, preferably a cardiac rhythm management device, capable of measuring transthoracic impedance and for sensing a level of physical activity is implanted in a patient. The transthoracic impedance signal is processed to obtain an estimate of the subject's minute ventilation, respiratory rate and tidal volume. From accelerometer measured activity, an estimate is obtained of oxygen uptake and carbon dioxide production. Ratios of tidal volume to respiratory rate, tidal volume to inspiratory time, minute ventilation to carbon dioxide production and oxygen uptake to heart rate are meaningftil status indicators for assessing the efficacy of particular therapy regimens to CHF patients.

Abstract: Exertion levels of a patient are measured by monitoring signals from adaptive-rate sensors such as an accelerometer and or a minute ventilation sensor; sensor data is collected for conversion into metabolic equivalent measurements. The data obtained can be used to evaluate patient physical activity levels and can be used to assess the patient's condition and change pacing therapy or other treatments accordingly. An automatic adjustment of the adaptive-rate pacing therapy may be based on the activity levels detected by the metabolic equivalent measurements made by the pacemaker.

Abstract: An ischemia detector has a patient workload sensor and a patient breathing sensor which emits a signal representing sensed workload, and a patient breathing sensor which emits a signal representing sensed breathing activity of a patient. These signals are supplied to a detector unit which identifies a state of ischemia upon an occurrence of a predetermined relation between the sensed workload and the sensed breathing activity. This predetermined relation is a sensed low workload and a simultaneously sensed high breathing activity.

Abstract: In a pacemaker, a method and apparatus for providing rate response in proportion to the patient's metabolic demand for cardiac output as determined in response to the patient's breathing rate or respiratory minute ventilation or contraction strength, optionally augmented by the patient's activity level. An implantable pulse generator (IPG) has one or more pacing leads having a proximal end coupled to the IPG and a distal end in contact with a patient's heart. A pressure wave transducer mounted in the IPG in relation to the proximal end of the pacing lead senses pressure waves transmitted from the distal end of the pacing lead to the proximal end thereof. The pressure waves originate from disturbances imparted to the lead by heart contractions and breathing. A further isolated, reference sensor is also incorporated into the IPG in a similar fashion. An activity signal processor is coupled to the pressure wave or reference sensor for providing a patient activity physiologic signal.

Abstract: A cardiac rhythm management (CRM) device detects transthoracic impedance, extracts ventilation or other information, and adjusts a delivery rate of the CRM therapy accordingly. A four-phase sequence of alternating direction current pulse stimuli is periodically delivered to a patient's thorax. A transthoracic impedance signal is extracted using a weighted demodulation. Signal processing extracts ventilation information and removes cardiac stroke information using an adaptive lowpass filter. The adaptive filter cutoff frequency is based on the patient's heart rate; a higher cutoff frequency is provided for higher heart rates. Peak/valley detection indicates tidal volume, which is integrated to extract minute ventilation (MV). Short and long term averages are formed and compared to establish a MV indicated rate. Rate adjustment ignores MV information when a noise-measurement exceeds a threshold.

Abstract: A heart pacemaker which is arranged to stimulate the apical area of the heart. Stimulation of this area provides synchronous mechanical contraction of the left and right ventricles and overcomes the problem of pacemaker induced left bundle branch block type conduction disturbance. The pacemaker has a base surface which conforms to the apical area of the heart and mounts a plurality of epicardial stimulating electrodes. Selection of electrodes can be made to provide the most clinically appropriate stimulation. An opposite side of the pacemaker is arranged to contact the diaphragm and is provided with sensing electrodes to sense activity of the diaphragm and adjust pacing of the heart in accordance with changes in physical activity of the patient. The electrodes used are preferably of capacitive construction, having first and second capacitive plates either side of a dielectric formed by the body of the pacemaker.

Abstract: A system and method of providing for cardiac pacing which incorporates modulation of the pacing rate in order to minimize variations in ventricular power output, e.g., variation related to patient respiratory phases. In a preferred embodiment, pacing rate is increased during inspiration relative to expiration, to restore a measure of the normal rate modulation which occurs in a normal person. Patient respiration is monitored and a respiration signal is processed to determine the timing of rate modulation. Parameters representative of respiratory changes, such as right ventricular volume and right ventricular blood pressure are also monitored and, together with respiration amplitudes changes, are used to determine an incremental rate signal for controlling the extent of rate variation.

Abstract: A cardiac rhythm management (CRM) device detects transthoracic impedance, extracts ventilation or other information, and adjusts a delivery rate of the CRM therapy accordingly. A four-phase sequence of alternating direction current pulse stimuli is periodically delivered to a patient's thorax. A transthoracic impedance signal is extracted using a weighted demodulation. Signal processing extracts ventilation information and removes cardiac stroke information using an adaptive lowpass filter. The adaptive filter cutoff frequency is based on the patient's heart rate; a higher cutoff frequency is provided for higher heart rates. Peak/valley detection indicates tidal volume, which is integrated to extract minute ventilation (MV). Short and long term averages are formed and compared to establish a MV indicated rate. Rate adjustment ignores MV information when a noise-measurement exceeds a threshold.

Abstract: A device for determining the respiration rate and/or respiration depth of a patient includes a sensor for sensing heart sounds and an analyzer for analyzing the variation of the amplitude of the sensed heart sounds to determine the respiration rate and/or respiration depth from this amplitude variation. An apparatus for monitoring the respiration of a patient includes such a device and the analyzer is arranged to determine an anomaly in the amplitude variation of the sensed heart sounds as an indication of a respiration anomaly.

Abstract: A heart pacemaker which is arranged to stimulate the apical area of the heart. Stimulation of this area provides synchronous mechanical contraction of the left and right ventricles and overcomes the problem of pacemaker induced left bundle branch block type conduction disturbance. The pacemaker has a base surface which conforms to the apical area of the heart and mounts a plurality of epicardial stimulating electrodes. Selection of electrodes can be made to provide the most clinically appropriate stimulation. An opposite side of the pacemaker is arranged to contact the diaphragm and is proved with sensing electrodes to sense activity of the diaphragm and adjust pacing of the heart in accordance with changes in physical activity of the patient. The electrodes used are preferably of capacitive construction, having first and second capacitive plates either side of a dielectric formed by he body of the pacemaker.