Telectronics Pacing Systems, Inc.

Randy T Wells

Bruce M Steinhaus

Ken Koestner

A patient-implantable cardiac stimulation apparatus adapted to measure body impedance, derive at least one physiological parameter from the impedance measurement, sample a time sequence of the physiological parameter and transmit the sequence to an external monitoring device for display and analysis. The apparatus may also sense intracardiac electrograms while it is measuring body impedance and deriving the physiological parameter, in which case it formats and transmits a combined intracardiac electrogram and physiological signal to the monitoring device.

Apparatus and method for measuring, formatting and transmitting combined

A method and apparatus for aligning periodic cardiac signal waveforms for the purpose of signal averaging over a number of cardiac cycles. The aligning method and apparatus sense cardiac electrical signals over a number of cardiac cycles, store a template characterizing these signals, reduce the data rate of the same sensed signals by temporal data compression, and store a compressed template sequence. Subsequently, the method and apparatus perform signal averaging by monitoring cardiac electrical signals, storing samples of these signals, temporally compressing these samples and scan correlating the compressed samples with the previously stored compressed template sequence to derive correlation coefficients. Thereafter, the method and apparatus utilize the maximum correlation coefficient to roughly align the monitored waveform with the averaged signal, and then they scan correlate a portion of the noncompressed monitored waveform adjacent to the maximum correlation coefficient with a corresponding portion of the non-compressed template to provide precise alignment of the monitored waveform with the averaged signal.

Signal averaging of cardiac electrical signals using temporal data

A method and apparatus for detecting cardiac arrhythmias in a patient's heart is disclosed. The monitoring method and apparatus sense cardiac electrical signals when the heart is functioning in a known cardiac state, then characterize this known cardiac state by storing a temporally compressed template of time sequence samples. The method and apparatus allow testing during multiple different cardiac states and provide for storage of templates associated with each state. Subsequently, when the heart is functioning in an unknown cardiac state, the method and apparatus monitor cardiac electrical signals by temporally compressing samples and scan correlating these samples with the previously stored template sequences to derive correlation coefficients. The method and apparatus then use these correlation coefficients to characterize cardiac function.

Detection of cardiac arrhythmias using correlation of a cardiac

A method and apparatus for storing a representation of a cardiac signal by compressing the data using scan correlation and temporal data compression techniques. The method and apparatus sense cardiac signals when the heart is functioning in a known cardiac state, then characterize this known state by storing a temporally compressed template of time sequence samples. The method and apparatus may perform testing for multiple different cardiac states and store templates associated with each state. Subsequently when the heart is functioning in an unknown cardiac state, the method and apparatus monitor cardiac signals by temporally compressing samples and scan correlating these samples with the previously stored templates to derive correlation coefficients. These correlation coefficients are a basis for identifying and classifying cardiac signal waveforms. For waveforms which correlate highly with a particular template, analysis of the timing of the maximum correlation coefficient provides a fiducial time which designates the time relationship of waveforms within different cardiac cycles. The method and apparatus store information in the form of templates, fiducial timing markers, and waveform occurrence counts. This data provides the information necessary to subsequently reproduce a long-term signal record.

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Littleton, CO, United States of America

Randy T Wells