Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. in this case, outputs representing the cardiac electrical signals are also output.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: An apparatus for outputting heart sounds includes an implantable system and an external system. The implantable system includes a sensor for generating sensed signals representing detected heart sounds, an interface circuit and a control circuit for receiving the sensed signals, generating data representing the heart sounds therefrom, and transmitting the data to the external system via the interface circuit. The external system includes an interface circuit for communicating with the implantable system, and a control circuit for receiving the data representing the heart sounds and for generating control signals that cause an output device to generate outputs representing the sounds. The implantable system may also include a sensor(s) for detecting cardiac electrical signals. In this case, outputs representing the cardiac electrical signals are also output.

Abstract: A cardiac lead introducing apparatus, the cardiac lead introducing apparatus having a sleeve with a peripheral surface, a first end and a second end, where the sleeve includes an opening extending from the first end to the second end and adapted to hold at least a portion of a cardiac lead. The cardiac lead introducing apparatus further includes a first slit extending from the peripheral surface to the opening and from the first end to the second end which permits the sleeve to separate so the cardiac lead can pass through the cardiac lead introducing apparatus without any longitudinal motion of the device with respect to the cardiac lead. In one embodiment, the diameter of the opening is smaller than the outer diameter of the cardiac lead which permits the cardiac lead to be held static within the introducing apparatus as the lead connector of the cardiac lead is inserted into the socket of an implantable pulse generator connector block.

Abstract: An implantable electronic circuit for monitoring a patient's aerobic capacity includes an accelerometer for detecting the onset and termination of a period of exercise and a means for measuring the patient's minute volume. By computing the time interval from the cessation of exercise to the point where the patient's minute volume reaches a predetermined value at or near an at-rest value thereof, a measure of aerobic capacity relating to a patient's physical fitness can be determined.

Abstract: A cardiac pacing and sensing system includes a body implantable unit for generating tissue stimulation pulses and manipulating information based on sensed signals, and a catheter for transmitting pulses from the unit to a pacing electrode adjacent myocardial tissue. The unit incorporates circuitry for generating response values, one associated with each stimulation pulse, based on a predetermined characteristic or parameter of the signals evoked by the pulses. To evaluate the efficacy of the parameter in distinguishing capture versus non-capture, the stimulation pulses are generated according to a protocol of high energy pulses guaranteed to effect capture interspersed with low energy pulses guaranteed not to effect capture. Data, accumulated and sorted into separate "capture" and "non-capture" sets, provides respective capture and non-capture composite values.

Abstract: A dual chamber pacemaker incorporating an adaptive PVARP for breaking pacemaker mediated tachycardia episodes and adjusting the PVARP interval in a way that reduces future incidences of PMT without extending PVARP beyond what is required.

Abstract: A cardiac pacemaker having an automatic pulse rate response gain factor responsive to at least one cardiac-related physiological characteristic of a patient. The pacemaker includes a rate controller that comprises a detector for detecting a plurality of individual measurements of at least one physiological characteristic over each of a plurality of pre-determined time periods, with each of the individual measurements being an average of values detected over each of a respective multiple number of incremental time periods occurring within each of the pre-determined time periods. The pacemaker saves the highest measurement from one incremental time period of each of several consecutive pre-determined time periods, and these highest measurements are averaged. Thereafter, the rate controller adjusts the rate response gain factor or slope of the pulse rate in relation to the physiological characteristic measurement and a pre-determined target pulse rate.

Abstract: A rate adaptive cardiac rhythm management device in which the pacing rate is adjusted in accordance with changes in the patient's minute ventilation. An adaptive four-pole elliptic digital filter, preferably implemented in software, functions to attenuate any signal components due to cardiac activity and motion from the minute ventilation signal over the range of breathing frequencies encountered in going from a sedentary state to active exercise. The pacemaker incorporates a microprocessor-based controller that is programmed to compute from peak-to-peak excursions of the sensed parameter the instantaneous tidal volume. Likewise, it computes, using a zero-crossing technique, the breathing interval. Knowing the breathing interval and the instantaneous tidal volume, it is possible to compute minute ventilation over a predetermined time interval and it is that factor that is employed in developing the ultimate control signal used to vary the stimulating rate between a lower rate limit and an upper rate limit.

Abstract: A method for classifying cardiac arrhythmias by examining the atrial and ventricular activity of the heart. The atrial contraction rate and ventricular contraction rate are compared with each other when the ventricular rate exceeds a preset value. When the atrial rate exceeds the ventricular rate, the regularity of the atrial rate, ventricular rate, and time interval between atrial contraction and ventricular contraction are determined. Regularity is determined by computing the standard deviation of a variable and comparing the standard deviation with a predetermined fractional value of the variable. A therapy routine is provided depending on the classification of a detected arrhythmia and the level of the ventricular contraction rate.

Abstract: A encoding/decoding algorithm for storing cardiac cycle length data in a memory of a body implantable device. The data encoding is based on a Holter function for sequentially storing in addresses in memory data representative of cardiac cycle length intervals and data representative of changes in the cardiac cycle length intervals. The sequence of storing is dictated by the value of the time interval change data. If the value of the time interval change data is greater than the storage capacity of a single memory location, then the time interval data is stored in memory at two consecutive memory locations. On the other hand, if the magnitude of the timer interval data is within the storage capacity of a single memory cell, it is stored in memory at a single memory cell. When decoding the stored data, retrieval proceeds through the memory according to the value of the data stored so that the time interval data is reconstructed from the originally stored time interval data or change in time interval data.