摘要:
A memory device particularly useful in size-constrained electronic products, such as cardiac stimulators. To provide additional memory for such size-constrained products, memory chips are stacked one on top of another. The memory chips are configured to facilitate bonding without crossed contacts, using aligned bonding pads, vias, or castellations. Each memory chip also includes an address selection circuit that receives signals from one or more address lines to selectively enable and disable the memory chips in the stack.
摘要:
A method and apparatus for detecting failure or impending failure of a lead and for providing a warning to a patient or a patient's physician. The impedance of the lead is repeatedly measured and compared with certain impedance limits. If the measured impedance falls outside of these impedance limits, an alarm may be given to the patient, or a warning may be given to the patient's physician.
摘要:
An implantable medical device, such as a cardiac pacer, defibrillator or drug delivery system, includes a container housing the required power source and circuitry and a header portion molded or glued to the container housing. Sensors, including physiological parameter sensors as may be necessary to control and implement the operation of the implantable device, or a telemetry link, or both, are disposed and sealed within the header. The header may include electromagnetic focusing devices to enhance the performance of the sensors. The sensors may include two pulse oximetry sensors that provide differential measurements to improve detection of arterial blood flow.
摘要:
An implantable medical device includes a giant magnetoresistance ratio (GMR) sensor is used to detect the presence of a magnet in order to command the device to enter a predetermined mode of operation. The GMR responds to a modulated magnetic field generated by the programming of a command transmitter apparatus for non-invasive programming or controlling of the implanted device. The implantable medical device also monitors for the presence of a steady magnetic field to place the implanted device in a known, safe mode.
摘要:
A method and apparatus for monitoring balanced biphasic current pulses used for measuring impedance in cardiac stimulators involves detecting imbalances between the pulses of opposite polarity. Such imbalances are potentially harmful to cardiac stimulator users. By converting the two different pulse phases into potentials, a determination can be made as to whether adequately balanced pulses are being generated. If an imbalance is detected, corrective action can be taken quickly enough to avoid harmful effects to the stimulator user.
摘要:
A method and apparatus for detecting loss of cardiac pacing pulse amplitude includes a comparator for comparing the actual pulse voltage to a reference voltage. In one advantageous embodiment, the reference voltage is determined as a percentage of the programmed pulse amplitude. The comparison of the reference voltage and the actual voltage is latched at the time when a pulse is actually created to produce a signal indicative of whether the amplitude of the actual pulse exceeds the reference. When the amplitude falls below the reference, the system may take corrective action.
摘要:
Disclosed are apparatus and method for detecting electromagnetic interference (EMI), or noise, that may disrupt the proper operation of medical devices implantable in patients, such as cardiac stimulators. Circuitry of the detector of the invention is independent of other circuitry of the medical device. EMI is magnetically induced on an antenna that may be within the metal housing of the device in a receiver circuit, and the EMI signals are output to the noise detector. A variety of alert signals may be provided to the medical device circuitry to warn of the presence of EMI so that appropriate responses may be taken to insure the safety of the patient dependent on the device. The detector may share the telemetry antenna of the medical device, or utilize a separate, dedicated antenna to receive EMI. Alternative antennas external to the metal housing of the medical device include leads from the device to the heart of the patient, and a dedicated antenna in the non-metal header of the device.
摘要:
A cardiac simulation system including a patient warning apparatus. The cardiac stimulator is an implantable pacemaker or defibrillator or combination which can be programmed to automatically alter the voltage of its output stimulus, in particular, to increase the voltage of the output stimulus whenever a condition exists requiring patient notification or warning. A specialized auxiliary lead with a shunt circuit can be connected to a standard socket of a cardiac stimulator header and a standard lead, such as a cardiac pacemaker lead, can then be connected to the auxiliary lead. The auxiliary lead allows a stimulation electrode to be implanted near excitable tissue in a secure fashion to assure stimulation of tissue. The auxiliary lead includes an apparatus for shunting electrical current from the standard stimulation electrode implanted in or near the patient's heart to the auxiliary electrode in the presence of a stimulation pulse with a voltage at or above a preselected level.
摘要:
A cardiac simulator including a patient warning apparatus, having an electrically conductive suture point in electrical communication with the patient warning apparatus. An electrically conductive suture passed through the suture point connects said stimulator mechanically and electrically to excitable tissue such as skeletal tissue. Inside the suture point is a connection for assuring a reliable electrical contact between the suture point and the suture. The cardiac stimulator automatically alters the peak voltage of its output stimulus whenever a condition exists requiring patient notification or warning. A specialized shunt circuit mounted within the stimulator or in the header of the stimulator re-directs electrical current from the standard stimulation electrode to the electrically conductive suture point. A controlled switch may be mounted within a hermetically sealed can of the stimulator to re-direct a stimulation pulse to the suture point. The controlled switch could also be mounted in the header. A dedicated stimulation circuit could also be used. The connection inside the suture point may comprise conductive metal fingers or bristles, a toroidal, multi-filar or woven conductor or an electrically conductive polymer.
摘要:
A cardiac simulator including a patient warning apparatus, having a sensor for detecting patient reaction to a warning stimulus and means for adjusting the magnitude of said warning stimulus to obtain a preselected level of reaction. The cardiac stimulator is an implantable pacemaker or defibrillator or combination which can be programmed to produce a warning stimulus whenever a condition exists requiring patient notification or warning. A warning pulse stimulus generator directs electrical current to a warning electrode. Alternatively, a controlled switch may re-direct a stimulation pulse to the warning electrode. The sensor for detecting the reaction of the patient to the applied warning stimulus may be an accelerometer or motion/vibration transducer or other sensor capable of detecting a reaction to a warning stimulus. Means for adjusting the level of the stimulus directed to the patient's skeletal muscle regulate the stimulus until a pre-selected magnitude of reaction has been achieved. The reaction is also maintained below a pre-selected maximum to avoid discomfort to the patient.