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: A system and automated method for assessing ventricular synchrony in ambulatory patients is provided including at least one mechanical sensor (e.g., accelerometer, tensiometric sensor, force transducer, and the like) operatively coupled to a first myocardial location in order to measure a wall motion signal of a first chamber, and a second mechanical sensor operatively coupled to a second myocardial location in order to measure a wall motion signal of a second chamber. The wall motion signals are processed in order to identify the time at which a fiducial (e.g., an inflection point, a threshold crossing, a maximum amplitude, etc.) occurs for each respective signal. The temporal separation between the fiducial points on each respective signal is measured as a metric of ventricular synchrony and can be optionally utilized to adjust pacing therapy timing to improve synchrony.

Abstract: A system and method for monitoring respiration including sensing a signal that varies with respiration, deriving a respiration parameter, applying criteria for detecting a respiration disturbance and determining one or more respiratory disturbance metrics. The system preferably includes an implantable sensor with an associated implantable medical device such that chronic respiration monitoring is possible. The implantable medical device may execute methods for detecting and measuring respiratory disturbances or may store data to be transferred to an external device for detecting and measuring respiratory disturbances. Respiratory disturbance detection may trigger a responsive action such as physiological data storage, a change in therapy delivery, or a clinician warning. Assessment of cardiac function may be made based on metrics of respiratory disturbances or a measure of circulatory delay time following detection of a respiratory disturbance.

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: The invention relates generally to a system and method for monitoring and automatically delivering a therapy for sleep-related disordered breathing. In one form the present invention relates to an external device for monitoring for sleep-related disordered breathing in communication with an implantable medical device for delivering an electrical stimulation therapy. In another form the present invention relates to an implantable medical device for detecting sleep-related disordered breathing episode(s) and an external apparatus (e.g., a CPAP machine) for providing therapy to terminate, and/or reduce, said episode(s). In this form of the invention, the implantable medical device communicates with the external apparatus so that the therapy provided corresponds in magnitude and duration to the severity and/or length of the episode(s).

Abstract: The invention relates generally to a system and method for monitoring and automatically delivering a therapy for sleep-related disordered breathing. In one form the present invention relates to an external device for monitoring for sleep-related disordered breathing in communication with an implantable medical device for delivering an electrical stimulation therapy. In another form the present invention relates to an implantable medical device for detecting sleep-related disordered breathing episode(s) and an external apparatus (e.g., a CPAP machine) for providing therapy to terminate, and/or reduce, said episode(s). In this form of the invention, the implantable medical device communicates with the external apparatus so that the therapy provided corresponds in magnitude and duration to the severity and/or length of the episode(s).

Abstract: A system and method for monitoring respiration including sensing a signal that varies with respiration, deriving a respiration parameter, applying criteria for detecting a respiration disturbance and determining one or more respiratory disturbance metrics. The system preferably includes an implantable sensor with an associated implantable medical device such that chronic respiration monitoring is possible. The implantable medical device may execute methods for detecting and measuring respiratory disturbances or may store data to be transferred to an external device for detecting and measuring respiratory disturbances. Respiratory disturbance detection may trigger a responsive action such as physiological data storage, a change in therapy delivery, or a clinician warning. Assessment of cardiac function may be made based on metrics of respiratory disturbances or a measure of circulatory delay time following detection of a respiratory disturbance.

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: The present invention provides a method and apparatus for detecting and monitoring obstructive sleep apnea. The apparatus includes an intracardiac impedance sensor to measure intracardiac impedance, a movement sensor to measure an amount of movement of a patient, and a controller operatively coupled to said intracardiac impedance sensor and said movement sensor, said controller adapted to receive at least one of an intracardiac impedance and the amount of movement of the patient and detect obstructive sleep apnea based upon said intracardiac impedance and said movement.

Abstract: An apparatus and method for treating sleep apnea includes a control unit in electrical communication with a lead. The control unit is capable of outputting a sleep apnea interruption pulse to stimulate at least one of a phrenic nerve and a diaphragm. Specifically, an implanted medical device (IMD) such as an ICD or a pacemaker paces the heart and a mode switch algorithm changes the pacing output to stimulate at least one of a phrenic nerve and diaphragm when sleep apnea is detected by the control unit. The method includes determining if the patient is experiencing sleep apnea and outputting a sleep apnea interruption pulse to the at least one of a phrenic nerve and a diaphragm. The control unit may be incorporated with the IMD. In another embodiment, the control unit may be in wireless communication with the IMD and positioned outside a patient's body.

Abstract: Enzymes are immobilized on activated carbon supports at high load levels and with high stability by reacting an activated carbon support with a carbodiimide or an isoxazolium salt to form active organic radicals on the surface of the activated carbon support and thereafter treating the carbon support with an enzyme solution to immobilize the enzyme on the carbon support. The immobilization of enzymes on activated carbon provides immobilized enzymes which are easily handled and which are stabilized against denaturation by hydrogen peroxide.

Abstract: Enzymes are immobilized on activated carbon supports at high load levels and with high stability by a procedure whereby a carbon support is first activated with a water-soluble carbodiimide derivative which forms a highly reactive intermediate with carboxyl and other active organic radicals on the surface of the carbon support; thereafter the complex of the carbon and carbodiimide is treated with an enzyme solution whereby the enzyme displaces the carbodiimide and forms a carbon-enzyme complex wherein the enzyme is immobilized and yet the carbon retains its surface activity. Preferred immobilizing agents are quaternary ammonium forms of aminocarbodiimides or hydrochloric acid salts of water-soluble carbodiimides. The immobilization of the enzymes on activated carbon provides materials which are easily handled and which are stabilized against denaturation by hydrogen peroxide.