Abstract: Methods and apparatus for communication of implantable medical device (IMD) information, including confirmation of programming and programmed parameter values, operating modes and programmed changes thereof and data stored in the IMD, by emission of audible sounds by the IMD are disclosed. The IMD includes an audio transducer that emits audible sounds including voiced statements or musical tones stored in analog memory correlated to a programming or interrogation operating algorithm or to a warning trigger event. The audible sounds can comprise the sole uplink transmission or may augment the contemporaneous uplink RF transmission of stored data, and/or programmed operating modes and parameters and/or device operations and states in an interrogation or during programming. To conserve energy, the audible sounds accompanying interrogation and programming of the IMD are at a low volume that preferably cannot be heard without use of an external audio amplifier or stethoscope.

Abstract: Methods and apparatus for communication of implantable medical device (IMD) information, including interrogation of programmed parameter values, operating modes and conditions of operation, confirmation of programmed changes thereof, interrogation of data stored in the IMD, and patient warnings or other messages by RF transmission of audible sounds generated by the IMD are disclosed. The IMD includes an RF transmitter that broadcasts or transmits audible sounds including voiced statements or musical tones stored in analog memory correlated to a programming or interrogation operating algorithm or to a warning trigger event. The broadcast radio signal is received, and the audible sounds are demodulated and reproduced by a radio receiver as voiced statements or musical tones that convey human understandable messages comprising IMD information generated during programming and interrogation sessions and warnings or status messages to the patient at other.

Abstract: A current limiting apparatus that is adapted to be operatively connected as part of a conductive loop formed by a medical device implanted within a living organism having electrically excitable tissue. This apparatus limits unwanted current in the conductive loop that may be induced by a significant level of an external signal such as a time-alternating electromagnetic field. This apparatus includes a switch for introducing a high impedance into the conductive loop when the switch is turned off. The apparatus also includes a control circuit that controls the switch to be turned on when the conductive loop should be closed to stimulate the electrically excitable tissue for a therapeutic effect. The control circuit turns the switch off whenever the living organism enters an area having a significant level of external signal that may induce unwanted current in the conductive loop to limit the unwanted current.

Abstract: A current limiting apparatus that is adapted to be operatively connected as part of a conductive loop formed by a medical device implanted within a living organism having electrically excitable tissue. This apparatus limits unwanted current in the conductive loop that may be induced by a significant level of an external signal such as a time-alternating electromagnetic field. This apparatus includes a switch for introducing a high impedance into the conductive loop when the switch is turned off. The apparatus also includes a control circuit that controls the switch to be turned on when the conductive loop should be closed to stimulate the electrically excitable tissue for a therapeutic effect. The control circuit turns the switch off whenever the living organism enters an area having a significant level of external signal that may induce unwanted current in the conductive loop to limit the unwanted current.

Abstract: An implantable anti-arrhythmia system which includes a spinal cord stimulator and an implantable heart rhythm monitor, coupled to control the spinal cord stimulator. The implantable heart monitor is adapted to detect the occurrence of tachyarrhythmias or of precursors thereto and in response, trigger the operation of the spinal cord stimulator in order to prevent occurrences of tachyarrhythmias and/or as a stand-alone therapy for termination of tachyarrhythmias and/or to reduce the level of aggressiveness required of an additional therapy such as antitachycardia pacing, cardioversion or defibrillation. The device in most embodiments is expected to include a mechanism for delivering an electrical anti-tachyarrhythmia therapy such as pacing, cardioversion or defibrillation in response to detection of a tachyarrhythmia. However, in some embodiments the spinal cord stimulator may be the only electrical stimulator included in the system.

Abstract: Methods and apparatus for communication of implantable medical device (IMD) information, including confirmation of programming and programmed parameter values, operating modes and programmed changes thereof and data stored in the IMD, by emission of audible sounds by the IMD are disclosed. The IMD includes an audio transducer that emits audible sounds including voiced statements or musical tones stored in analog memory correlated to a programming or interrogation operating algorithm or to a warning trigger event. The audible sounds can comprise the sole uplink transmission or may augment the contemporaneous uplink RF transmission of stored data, and/or programmed operating modes and parameters and/or device operations and states in an interrogation or during programming. To conserve energy, the audible sounds accompanying interrogation and programming of the IMD are at a low volume that preferably cannot be heard without use of an external audio amplifier or stethoscope.

Abstract: Methods and apparatus for confirming programming of implantable medical device (IMD) operating parameter values and operating modes by emission of audible sounds by the IMD are disclosed. The IMD includes an audio transducer that emits audible sounds including voiced statements or musical tones stored in analog memory correlated to a programming or interrogation operating algorithm or to a warning trigger event. The audible sounds can comprise the sole uplink transmission or may augment the contemporaneous uplink RF transmission of stored data, and/or programmed operating modes and parameters and/or device operations and states in an interrogation or during programming. To conserve energy, the audible sounds accompanying interrogation and programming of the IMD are at a low volume that preferably cannot be heard without use of an external audio amplifier or stethoscope.

Abstract: Methods and apparatus for interrogation of implantable medical device (IMD) information, including programmed parameter values, operating modes and programmed changes thereof and data stored in the IMD, by emission of audible sounds by the IMD are disclosed. The IMD includes an audio transducer that emits audible sounds including voiced statements or musical tones stored in analog memory correlated to a programming or interrogation operating algorithm or to a warning trigger event. The audible sounds can comprise the sole uplink transmission or may augment the contemporaneous uplink RF transmission of stored data, and/or programmed operating modes and parameters and/or device operations and states in an interrogation or during programming. To conserve energy, the audible sounds accompanying interrogation and programming of the IMD are at a low volume that preferably cannot be heard without use of an external audio amplifier or stethoscope.

Abstract: Methods and apparatus for confirming programming of implantable medical device (IMD) operating parameter values and operating modes by emission of audible sounds by the IMD are disclosed. The IMD includes an audio transducer that emits audible sounds including voiced statements or musical tones stored in analog memory correlated to a programming or interrogation operating algorithm or to a warning trigger event. The audible sounds can comprise the sole uplink transmission or may augment the contemporaneous uplink RF transmission of stored data, and/or programmed operating modes and parameters and/or device operations and states in an interrogation or during programming. To conserve energy, the audible sounds accompanying interrogation and programming of the IMD are at a low volume that preferably cannot be heard without use of an external audio amplifier or stethoscope.

Abstract: Methods and apparatus for interrogation of implantable medical device (IMD) information, including programmed parameter values, operating modes and programmed changes thereof and data stored in the IMD, by emission of audible sounds by the IMD are disclosed. The IMD includes an audio transducer that emits audible sounds including voiced statements or musical tones stored in analog memory correlated to a programming or interrogation operating algorithm or to a warning trigger event. The audible sounds can comprise the sole uplink transmission or may augment the contemporaneous uplink RF transmission of stored data, and/or programmed operating modes and parameters and/or device operations and states in an interrogation or during programming. To conserve energy, the audible sounds accompanying interrogation and programming of the IMD are at a low volume that preferably cannot be heard without use of an external audio amplifier or stethoscope.

Abstract: A system for insertion of a fiber optic diagnostic sensor into the human body. The sensor is of the type which functions by emission of light into the body and reception of light reflected from the body. In particular, the system is intended for use with fiber optic reflectance oximeters. The fiber optic sensor is inserted into an introducer catheter, and coupled to monitoring equipment and activated as the sensor is advanced through the introducer catheter. By appropriately filtering or otherwise processing the signal indicative of reflected light received by the sensor, its position relative to the end of the introducer catheter can be determined. This allows for accurate insertion of the fiber optic sensor, regardless of the length of the introducer catheter and regardless of the length and/or number of fittings or manifolds through which the fiber optic sensor must pass.

Abstract: A fiber-optic sensor for measuring a parameter of a test fluid, including a chemical sensor, incorporating a dye composition which displays changes in its optical properties correlated to changes in the parameter to be measured. The sensor is coupled to an apparatus including a light source, and means for measuring light received from said sensor at three different peak wavelengths. The first wavelength is chosen such that the optical characteristics of the dye with respect to that wavelength do not change significantly with changes in the parameter to be measured. The second and third wavelengths are chosen such that optical characteristics of the dye with respect to these wavelengths do change along with changes in the parameter to be measured, and also change as a function of temperature. The light received from the sensor at first, second and third wavelengths is compared to determine the temperature of the test fluid and to provide a temperature correction for the parameter to be measured.

Abstract: A waveform detection system for use in a pacemaker for distinguishing normal beats from ectopic or abnormal beats for example, such as those involving ventricular tachycardia, ventricular flutter or fribrillation, premature ventricular beats, supraventricular tachycardia, retrograde conduction; and in dual chamber or atrial applications those involving atrial tachycardia and atrial flutter or fibrillation. The term "abnormal" is employed herein to mean all abnormal beats including those specified above. In the system of the illustrated embodiment a sense amplifier is employed for initiating a counter in response to a detected cardiac event and a voltage controlled oscillator is used for converting the instantaneous value of the applied waveform to a bit rate delivered to the counter. The morphology or shape of the physiological waveform is represented by a number present in the counter at the end of the counting cycle which allows for a therapy decision to be made.

Abstract: A programmable cardiac pacemaker pulse generator utilizing digital circuitry for controlling the provision of cardiac stimulating pulses. The pulse generator is capable of having the rate, the pulse width, the pulse amplitude, the refractory period, the sensitivity and the mode of operation programmed. In addition, the pulse generator can have the output inhibited and can respond to programming signals causing a threshold margin test to be performed, effects of closure of the reed switch overridden, a hysteresis function added and a high rate exceeding the normal upper rate limit programmed. Many of the programmable functions of the pulse generator can either be programmed on a permanent or a temporary basis. The pulse generator further includes means for signaling the acceptance of a programming signal, and means to reset the program acceptance circuit if extraneous signals are detected as programming signals.

Abstract: A pacer subsystem for detecting the existence of tachyarrhythmia including means for measuring the average time interval between successive heart beats and for comparing a sample beat with both a percentage of this average, and with a preset time interval. If the sample beat period is less than both criteria, it is classified as a tachy beat. If the sample beat is longer than either time interval it is classified as a non-tachy beat. Sequences of tachy beats are used to initiate an appropriate therapeutic stimulation regime.

Abstract: A body stimulation system including external components for generating and transmitting programming signals and implantable components including a signal generator with at least one alterable operating characteristic, a stimulation signal delivering system and circuit responsive to receive programming signals for establishing the operating characteristic in predetermined correspondence therewith. The stimulation signal delivering system is connected to the operating characteristic establishing circuitry for receiving the programming signals. In a preferred embodiment, the external components are prevented from transmitting programming signals during a stimulation signal and, more preferably, for a predetermined period following a stimulation signal. The predetermined period may be established such that the external system is activated during the refractory period of the tissue being stimulated.

Abstract: A programmable cardiac pacemaker pulse generator utilizing digital circuitry for controlling the provision of cardiac stimulating pulses. The pulse generator is capable of having the rate, the pulse width, the pulse amplitude, the refractory period, the sensitivity and the mode of operation programmed. In addition, the pulse generator can have the output inhibited and can respond to programming signals causing a threshold margin test to be performed, effects of closure of the reed switch overridden, a hysteresis function added and a high rate exceeding the normal upper rate limit programmed. Many of the programmable functions of the pulse generator can either be programmed on a permanent or a temporary basis. The pulse generator further includes means for signaling the acceptance of a programming signal, and means to reset the program acceptance circuit if extraneous signals are detected as programming signals.

Abstract: A cardiac pacemaker of the type responsive to heart activity to affect the operation of the pacemaker. Detecting circuitry is provided having a differential input and an essentially polarity independent degree of response to sensed signals. A single polarity output signal is provided representative of sensed signals of either polarity. In a preferred embodiment, a differential input and differential output preamplifier is responsive to sensed signals to provide output signals of opposite polarity but like absolute value. An absolute value circuit responds to the opposite polarity signals to provide a single polarity output signal, the output signal being the same polarity without regard to the polarity of the sensed signals.

Abstract: A pacer having an upper and lower rate limit system for preventing pacer malfunction from producing pacer output pulses above or below preset maximum and minimum rates.

Abstract: A programmable cardiac pacemaker pulse generator utilizing digital circuitry for controlling the provision of cardiac stimulating pulses. The pulse generator is capable of having the rate, the pulse width, the pulse amplitude, the refractory period, the sensitivity and the mode of operation programmed. In addition, the pulse generator can have the output inhibited and can respond to programming signals causing a threshold margin test to be performed, effects of closure of the reed switch overridden, a hysteresis function added and a high rate exceeding the normal upper rate limit programmed. Many of the programmable functions of the pulse generator can either be programmed on a permanent or a temporary basis. The pulse generator further includes means for signaling the acceptance of a programming signal, and means to reset the program acceptance circuit if extraneous signals are detected as programming signals.