Importance

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Abstract

The respiratory function of a patient is measured for diagnostic purposes using a cardiac rhythm management device. Monitoring of the respiratory activity is initiated after a microprocessor in the cardiac rhythm management device determines that the patient has been at rest for a predetermined length of time. A respiration related signal is derived from either an accelerometer signal or from an impedance sensor, depending upon which produces a signal has the higher signal-to-noise ratio. The signal from either the accelerometer or impedance measuring mechanism is low-pass filtered to obtain a respiratory signal component. The respiratory signal component is digitized and sent to the microprocessor for analysis. The microprocessor can be programmed in either of two modes of analysis. In the first mode, the peak-to-peak values of the respiratory signal component over a number of fixed time interval is summed, obtaining the minute volume. In the second method, the entire waveform history during the fixed time interval is stored in the microprocessor. The stored information is then telemetered out to the physician when interrogated. The physician may then review the information and then determines the efficacy of a treatment regimen administered to the patient.

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First Claim