Abstract: An improved apparatus and method for determining the cardiac output of a living subject. The improved apparatus generally comprises one or more electrode assemblies or patches affixed to the skin of the subject in the vicinity of the thoracic cavity. In one embodiment, the apparatus comprises a constant current source impedance cardiography (ICG) monitor adapted as a stand-alone system. In another embodiment, the apparatus comprises a module adapted for use with a host monitoring system, the latter providing ECG, blood pressure, and/or other inputs to the module. Method of detecting a loss of electrical continuity in one or more of the terminals of the electrode patch, and selecting between a plurality of signal inputs based on signal quality, are also disclosed.

Abstract: Electrical connector apparatus optimized for biomedical applications. In one embodiment, the connector apparatus comprises a low-cost simplified device having a unitary conductor element adapted to interface with an electrode terminal such as used in impedance cardiography (ICG) or electrocardiography (ECG). The unitary conductor is shaped so as to provide a high degree of electrical performance and signal stability, and also be highly reliable. The simplified structure of the connector (including the use of the unitary conductor element) allows it to be manufactured for very low cost, so as to be disposable if desired. Methods of manufacturing and operating the connector are also disclosed.

Abstract: An improved apparatus and method for evaluating, tuning and operating a physiologic stimulator such as an implantable pacemaker or defibrillator. In one exemplary embodiment, an impedance cardiography system is used to measure one or more cardiac functions such as stroke volume or mitral regurgitation as the parameters determining the operation of the pacemaker are varied, such as via a non-invasive pacemaker programming device. After a plurality of the parameters have been programmed in and corresponding measurements of stroke volume or mitral regurgitation obtained, the data is evaluated to determine one or more optimized parameter values.

Abstract: An improved apparatus and method for determining the cardiac output of a living subject. The improved apparatus generally comprises one or more electrode assemblies or patches affixed to the skin of the subject in the vicinity of the thoracic cavity. In one embodiment, the apparatus comprises a constant current source impedance cardiography (ICG) monitor adapted as a stand-alone system. In another embodiment, the apparatus comprises a module adapted for use with a host monitoring system, the latter providing ECG, blood pressure, and/or other inputs to the module. Method of detecting a loss of electrical continuity in one or more of the terminals of the electrode patch, and selecting between a plurality of signal inputs based on signal quality, are also disclosed.

Abstract: A telemetry base station for use in a system also including a patient worn EKG monitor and transmitter, and a physician monitoring station. The base station is microprocessor controlled, and includes a receiver for receiving FM EKG transmissions from the patient transmitter, an A to D converter, a conventional telephone set, used as an intercom to communicate with the physician, and a data modem which is used for digitized transmissions of the EKG signals. Base station functions including selection of data or voice transmission are controlled by a physician monitoring station. The base station includes simulated telephone ringing functions which assist in its use by patients without specialized training.

Abstract: Apparatus and technique for monitoring physiological parameters. An acoustic sensor or microphone is placed in close proximity to the chest of a patient having one or two prosthetic heart valves. These heart valves produce clicks characteristic of opening and closing action. The acoustic sensor picks up the sound of these clicks and transfers them as electrical energy to a transmitter unit. The transmitter unit processes the analog signal, converts it to a digital signal and establishes the key timing factors involved. This digital data is stored in a memory buffer within the transmitter. Subsequently, this information is modulated and placed on telephone lines for transmission to a central monitoring site. At the monitoring site a demodulator returns the data to baseband digital signals. A computer at the central monitoring site displays the information in the time domain and also converts the information for display in the frequency domain.

Abstract: Apparatus for technique for monitoring physiological parameters. An acoustic sensor or microphone is placed in close proximity to the chest of a patient having one or two prosthetic heart valves. These heart valves produce clicks characteristic of opening and closing action. The acoustic sensor picks up the sound of these clicks and transfers them as electrical energy to a transmitter unit. The transmitter unit processes the analog signal, converts it to a digital signal and establishes the key timing factors involved. This digital data is stored in a memory buffer within the transmitter. Subsequently, this information is modulated and placed on telephone lines for transmission to a central monitoring site. At the monitoring site a demodulator returns the data to baseband digital signals. A computer at the central monitoring site displays the information in the time domain and also converts the information for display in the frequency domain.

Abstract: Apparatus for monitoring and storing heart activity signals is disclosed as including a data processor illustratively in the form of a digital microprocessor. The monitoring and storing apparatus comprises a memory comprising first and second pluralities of storage locations, a circuit operating in a real time frame for sampling at a regular rate the patient's heart activity and for storing such sample signals in corresponding locations of said first plurality, an the data processor for processing the signals stored in the first plurality and for storing the processed signals in selected locations of said second plurality. The storage of the signals in the second plurality is performed in a second computer time frame and at a rate faster than the real time sampling rate. A sampling clock provides a sampling clock signal to the sampling circuit whereby the samples of the patient's heart activity are taken.

Abstract: Apparatus is disclosed for monitoring and storing electrical signals in a manner to detect the intervals between heartbeats and to provide a manifestation of whether the corresponding heart signals have a regular heart rhythm or not. Such apparatus comprises a memory having at least first and second areas, a circuit for receiving and sampling the heart signals, and a circuit for temporarily storing the heart sample signals in the first area. Further, there is included a circuit for processing or evaluating the heart signals stored in the first area to determine the occurrences of the patient's heartbeat and for determining the intervals between adjacent heartbeats. The determined intervals are stored in the second area and are evaluated to determine whether the patient's heart activity occurs with a regular rhythm. The monitoring and storing apparatus is operative over a monitoring period comprised of a plurality of trend sample intervals.

Abstract: Heart monitoring and storing apparatus is disclosed for evaluating heart activity signals to determine if valid, for identifying a characteristic of the valid heart activity signal, and for storing the signal into a corresponding location of a memory depending upon the characteristic of the heart activity signal. Such apparatus comprises the memory including a first area and a second area, and a circuit for sampling the heart activity signals and for storing the heart signal samples into corresponding locations of such first area. There is further included an evaluation circuit for determining whether the sampled heart activity signals as stored within the first area are valid and particularly if they indicate the occurrence of a heartbeat. An addressing circuit is provided for determining the various characteristics of a valid heart signal and for selectively addressing a location within said second area to store the valid heart signal of the corresponding characteristic.

Abstract: A medication dispenser in which medication to be dispensed is housed, including a member operable to allow medication access. The dispenser provides a medication alert signal at preselected times in accordance with a desired medication regimen. A medication access signal is provided when medication access is obtained. Data representative of the relative timing between a medication alert signal and a medication access signal is written into a readable memory whereby that data is available to a physician for evaluation. In a preferred embodiment, the data is representative of the time of occurrence of each medication alert signal and medication access signal. The interval between medication alert signals is selectively alterable.

Abstract: Cardiac monitoring and pacing apparatus comprising a first external unit for transmitting electromagnetic energy within the patient's body to be received by a second, surgically implanted unit within the patient's body and adapted to be solely powered by the transmitted electromagnetic energy. The first external unit transmits electromagnetic energy within the patient's body which is sensed and used to power the implanted unit, which stimulates, via pacing electrodes, the patient's heart. The internal unit also includes a monitoring circuit connected to the same pacing electrodes coupled to the patient's heart, for providing atrial and ventrical signals to be pulse-width modulated for transmission to the external unit. The external unit decodes the transmitted signals to provide diagnostic quality signals indicative of the patient's EKG.

Abstract: Cardiac monitoring apparatus comprising a first external unit for transmitting electromagnetic energy within the patient's body to be received by a second, surgically implanted unit within the patient's body and adapted to be solely powered by the transmitted electromagnetic energy. The internal unit includes a monitoring circuit connected via electrodes coupled to first and second sites of the patient's heart, for providing corresponding first and second signals to be first time multiplexed and then pulse-width modulated before being re-transmitted to the external unit. The external unit decodes the transmitted signals to provide diagnostic quality signals indicative of the patient's EKG.