Abstract: An infusion system for infusing a liquid into a body includes an external infusion device and a remote commander. The external infusion device includes a housing, a receiver, a processor and an indication device. The receiver is coupled to the housing and for receiving remotely generated commands. The processor is coupled to the housing and the receiver to receive remotely generated commands and to control the external infusion device in accordance with the commands. The indication device indicates when a command has been received and indicates when the command is being utilized to control the external infusion device so that the external infusion device is capable of being concealed from view when being remotely commanded. The remote commander includes a commander housing, a keypad for transmitting commands, and a transmitter for transmitting commands to the receiver of the external infusion device.

Abstract: A safety circuit system for a DC driven device for use with a fluid delivery system includes a first voltage potential DC power line, a second voltage potential DC power line, a controller and a safety circuit. The first voltage potential DC power line is coupled to provide a first voltage potential to the DC driven device, and the second voltage potential DC power line is coupled to provide a second voltage potential to the DC driven device such that the second voltage potential is different relative to the first potential. The controller controls at least the first voltage potential on the first voltage potential DC power line. The safety circuit has an enable state and a disable state, in which the default state is the disable state. The safety circuit is coupled to the controller, and the controller controls the safety circuit to place the safety circuit in the enable state independently of controlling the first voltage potential on the first voltage potential DC power line.

Abstract: In an implantable cardioverter-defibrillator and/or pacemaker, each having DDD pacing capabilities, an improved method of operation is described which dramatically increases the longevity of the implanted device by conserving battery power. The method comprises deactivating at least one unnecessary, power-consuming feature of the device until such feature is needed and then reactivating said feature only for so long as it is required by the patient. In a particular embodiment, the atrial sense amplifier is deactivated during normal operation of the implantable device, resulting in single-chamber sensing and pacing. Upon the occurrence of a predefined event, indicative of a need for dual-chamber sensing and pacing, the atrial sense amplifier is reactivated, the need for DDD pacing confirmed, and if appropriate, DDD pacing is begun. Once the patient's heart rate has returned to an acceptable level, the atrial sense amplifier is again deactivated and single-chamber sensing/pacing continued.

Abstract: A single-pass pacing and/or shocking lead system is capable of sensing cardiac signal in the atrium and the ventricle in a “bipolar fashion” using a three-electrode structure: a first electrode in the atruim, a second electrode in the ventricle just below the tricuspid valve, and a third in the ventricle.

Abstract: A medical device module for use in a system with a remote programmer and/or a personal data assistant (PDA) with at least one medical device includes a housing, at least one medical device and a processor. The housing is adapted to couple with the PDA. The at least one medical device interface is coupled to the housing for interfacing with the at least one medical device. The processor is coupled to the at least one medical device interface to process data from the at least one medical device. The processor is also capable of interfacing with the PDA.

Abstract: An annunciator is provided for an organ stimulating system which is implantable in the body of a patient. A stimulus signal generator such as an implantable cardioverter defibrillator which includes an energizing capacitor is encased in a housing for imparting an electrical stimulation signal to an organ, such as a heart, to be stimulated. The signal generator includes a sensor for sensing at least one of a plurality of physiological characteristics and apparatus for generating an electrical signal corresponding to the sensed physiological characteristic. A vibration generator responsive to that electrical signal is then operable to impart to the housing a subaudible vibration, that is, one having a frequency less than about 250 hertz, which is detectable by the patient.

Abstract: An implantable cardiac stimulation device includes a system for detecting noise in an electrogram signal. The system for detecting noise generates an event signal when the electrogram signal exceeds a threshold. A timer times a refractory time period responsive to an event signal. During the refractory time period, a zero crossing detector generates a zero crossing signal when the electrogram signal transitions between positive and negative values. A counter counts the zero crossing signals during the time period and a comparator determines if the counter reached a predetermined count during the time period. If the counter exceeds a programmable count, a noise detection flag is set and the controller is alerted to the presence of noise in its input signal.

Abstract: An external infusion device that infuses a fluid into an individual's body includes a housing, a reservoir, a drive system, a power supply, electrical elements, and a tab. The reservoir contains the fluid, and the drive system forces the fluid from the reservoir. The electrical elements control the power to the drive system to regulate the rate that fluid is forced from the reservoir. The tab mates with the housing, and contains at least one electrical element. The tab is removable, and may be replaced with a different tab. The different tab may change the rate fluid is forced from the reservoir. A tab may be removed from one external infusion device and installed in a different external infusion device. The tab may be limited to use in a predetermined number of external infusion devices and may include a power supply.

Abstract: An occlusion detection system detects an occlusion in a fluid path of an infusion pump. The infusion pump is for delivering fluid to a user. The infusion pump includes a housing, a motor, a reservoir, one or more drive train components, a sensor, and an electronics system. The motor is contained within the housing. The reservoir contains the fluid to be delivered. The one or more drive train components react to stimulus from the motor to force the fluid from the reservoir into the user. The sensor is positioned to measure a parameter associated with the motor or a drive train component, and the sensor produces three or more output levels across a range of measurements. The electronics system processes the senor output levels to declare when an occlusion exists.

Abstract: A safety circuit system for a DC driven device for use with a fluid delivery system includes a first voltage potential DC power line, a second voltage potential DC power line, a controller and a safety circuit. The first voltage potential DC power line is coupled to provide a first voltage potential to the DC driven device, and the second voltage potential DC power line is coupled to provide a second voltage potential to the DC driven device such that the second voltage potential is different relative to the first potential. The controller controls at least the first voltage potential on the first voltage potential DC power line. The safety circuit has an enable state and a disable state, in which the default state is the disable state. The safety circuit is coupled to the controller, and the controller controls the safety circuit to place the safety circuit in the enable state independently of controlling the first voltage potential on the first voltage potential DC power line.

Abstract: A Holter-type monitor system includes a remotely located data receiving device, an analyte sensor for producing signal indicative of a characteristic of a user, and a Holter-type recording device. The Holter-type recording device includes a housing, a sensor connector, a processor, and a data port. The sensor connector receives the produced signals from the analyte sensor. The processor is coupled to the sensor connector and stores the signals from the analyte sensor for delivery to the remotely located data receiving device. The recording device is coupled to the processor for downloading the stored signals to the remotely located data receiving device. The data receiving device may be a characteristic monitor, a data receiver that provides data to another device, an RF programmer, a medication delivery device (such as an infusion pump), or the like.

Abstract: In an ICD, a highly efficient biphasic defibrillation pulse is generated by switching at least two charged capacitors, e.g., three capacitors, from a parallel connection to various combinations of a parallel/series connection or a series connection during the first phase of the defibrillation pulse. Such mid-stream parallel/series connection changes of the capacitors steps up the voltage applied to the cardiac tissue during the first phase. A stepped-up voltage during the first phase, in turn, gives an extra boost to, and thereby forces additional charge (current) into, the cardiac tissue cells, and thereby transfers more charge to the membrane of the excitable cardiac cell than if the capacitors were continuously discharged in series. Phase reversal is timed with the cell membrane reaching its maximum value at the end of the first phase.

Abstract: An implantable cardiac device is disclosed having a converter that provides a digital electrocardiogram signal to a controller which is stored in memory or transmitted via the telemetry circuit in an improved compressed fashion. The improved compression scheme comprises sampling the electrogram signal, transmitting the starting value in an uncompressed format followed by a plurality of delta signals in a compressed format. The delta signals may be determined by subtracting successive signals or by subtracting a predicted value from the current value. In either case, the delta signal is then transmitted in a truncated number of bits, e.g., 2 or 4 bits. When the delta signal is too large to be represented in the compressed number of bits, the controller then provides an indicator signal followed by the delta signal in the uncompressed format. In addition, whenever successive delta signals are below a minimum threshold (e.g., zero), they may be compressed into a count.

Abstract: An improved sensor and related method for multi-axial measurement of motion for an implantable medical device is disclosed. The sensor has a wide variety of applications, including use as a cardiac wall motion sensor or a physical activity sensor. The sensor includes first and second conductors over which the motion measurements are made. A first transducer provides a first motion measurement indicative of sensor acceleration during a first phase, while a second transducer provides a second motion measurement indicative of sensor acceleration during a second phase. The first and second transducers are connected in parallel so as to provide the first and second motion measurements to an implantable medical device over the first and second conductors. The first and second phases are non-overlapping periods of time so that the motion measurements from each transducer are time division multiplexed. The sensor provides motion measurements that may either be compensated or uncompensated for temperature effects.

Abstract: An antitachycardia stimulation device that automatically adjusts its detection rate threshold as a function of a sensed physiological parameter indicative of cardiac rate. The implantable antitachycardia stimulation device includes heart rate detection circuitry and antitachycardia therapy circuitry for applying a specific antitachycardia therapy in the event that the detected heart rate falls within at least one tachycardia rate zone. The tachycardia rate zone is defined by a lower threshold limit, and may also be defined by an upper threshold limit if more than one rate zone is used. The lower threshold limit is automatically adjusted as a function of an independently sensed physiological parameter that predicts a normal or natural change in the heart rate. If more then one rate zone is used, other threshold limits may also be adjusted automatically as a separate function of the same sensed physiological parameter.

Abstract: A system for delivering low pain cardioversion shocks to the heart wherein the system provides a waveform to the heart for cardioversion purposes to result in less stimulation of sensory nerves surrounding the heart. In one embodiment, the system includes a controller and a plurality of controlled switches that can be configured so that the heart receives a waveform through one or more resistors from a capacitor. The controller is configured to manipulate the switches so that the waveform that is applied to the heart is applied for more than 10 milliseconds so that the ratio of stimulation of the cardiac cells to the stimulation of sensory cells is approximately one. In another embodiment, the controller configures the switches so that a first capacitor discharges to charge a second capacitor through a resistor wherein the second capacitor is in parallel with the heart.

Abstract: A microprocessor-controlled implantable cardiac stimulating device having a normal mode, an intermediate mode, and a backup pacing mode is provided. The device switches from one mode to another in response to the detection of any one of an address error, parity error, opcode error, or watchdog timer error. The microprocessor is shut down during the delivery of a cardioversion or defibrillation shock in order to prevent signals produced by the microprocessor from being subjected to transient electrical signals. The interrupt registers of the microprocessor are also disabled during the delivery of a cardioversion or defibrillation shock. In an alternative embodiment, an implantable cardiac stimulating device is provided with redundant microprocessors in order to detect malfunctions of the microprocessors.

Abstract: A cardiac event and arrhythmia detection system and method detects arrhythmic cardiac activity or other information from an electrogram signal of a heart. The system senses the electrogram signal through an electrogram lead, preliminarily processes the signal, and converts it to a plurality of discrete digital signals, each of which represents the magnitude of the electrogram signal at a prescribed sample time. The discrete digital signals are applied to both a cardiac event detector which has a dynamic threshold which is programmably adjustable so that T-waves are not sensed and a morphology detector. The morphology detector detects selected changes in the morphology (shape) of the electrogram signal, wherein such changes automatically control the sensitivity (gain and/or threshold) used to detect cardiac events. The occurrence of a prescribed amount of change in the detected morphology over time indicates the occurrence of a prescribed arrhythmic cardiac condition.

Abstract: Implantable leads incorporating accelerometer-based cardiac wall motion sensors, and a method of fabricating such leads, are provided. The cardiac wall motion sensors transduce accelerations of cardiac tissue to provide electrical signals indicative of cardiac wall motion to an implantable cardiac stimulating device. The implantable cardiac stimulating device may use the electrical signals indicative of cardiac wall motion to detect and discriminate among potentially malignant cardiac arrhythmias. In response to a detected abnormal cardiac rhythm, the cardiac stimulating device may deliver therapeutic electrical stimulation to selected regions of cardiac tissue.

Abstract: A microprocessor-controlled implantable cardiac stimulating device having a normal mode, an intermediate mode, and a backup pacing mode is provided. The device switches from one mode to another in response to the detection of any one of an address error, parity error, opcode error, or watchdog timer error. The microprocessor is shut down during the delivery of a cardioversion or defibrillation shock in order to prevent signals produced by the microprocessor from being subjected to transient electrical signals. The interrupt registers of the microprocessor are also disabled during the delivery of a cardioversion or defibrillation shock. In an alternative embodiment, an implantable cardiac stimulating device is provided with redundant microprocessors in order to detect malfunctions of the microprocessors.