Long-term electrocardiographic and physiological monitoring over a period lasting up to several years in duration can be provided through a continuously-recording subcutaneous insertable cardiac monitor (ICM). The sensing circuitry and the physical layout of the electrodes are specifically optimized to capture electrical signals from the propagation of low amplitude, relatively low frequency content cardiac action potentials, particularly the P-waves that are generated during atrial activation. In general, the ICM is intended to be implanted centrally and positioned axially and slightly to either the left or right of the sternal midline in the parasternal region of the chest. Additionally, the ICM includes an ECG sensing circuit that measures raw cutaneous electrical signals and performs signal processing prior to outputting the processed signals for sampling and storage.

A monitor recorder-implemented method for electrocardiography data compression and an electrocardiography monitor recorder with integral data compression are provided. A series of data items are obtained, each of the data items associated with a magnitude of an ECG signal sensed by a monitor recorder. A range is set for an initial one of the data items in the series. Each of the data items remaining in the series is processed, including: obtaining an estimation of probabilities of the data items appearing next to that data item in the series; dividing the further range into sub-ranges, each sub-range representing a fraction of the further range proportional to the probabilities of the next data items; selecting the sub-range corresponding to the data item next to that data item in the series; and representing the next data item by the selected sub-range in a non-volatile memory.

Described is an apparatus and method for data compression using compressive sensing in a wearable device. Described is also a machine-readable storage media having instruction stored thereon, that when executed, cause one or more processors to perform an operation comprising: receive an input signal from a sensor; convert the input signal to a digital stream; and symmetrically pad on either ends of the digital stream with a portion of the digital stream to form a padded digital stream.

An acoustic sensor is provided according to certain aspects for non-invasively detecting physiological acoustic vibrations indicative of one or more physiological parameters of a medical patient. The sensor can include an acoustic sensing element configured to generate a first signal in response to acoustic vibrations from a medical patient. The sensor can also include front-end circuitry configured to receive an input signal that is based at least in part on the first signal and to produce an amplified signal in response to the input signal. In some embodiments, the sensor further includes a compression module in communication with the front-end circuitry and configured to compress portions of at least one of the input signal and the amplified signal according to a first compression scheme, the compressed portions corresponding to portions of the first signal having a magnitude greater than a predetermined threshold level.

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Physiological monitoring can be provided through a lightweight wearable monitor that includes two components, a flexible extended wear electrode patch and a reusable monitor recorder that removably snaps into a receptacle on the electrode patch. The wearable monitor sits centrally (in the midline) on the patient's chest along the sternum oriented top-to-bottom. The placement of the wearable monitor in a location at the sternal midline, with its unique narrow hourglass-like shape, significantly improves the ability of the wearable monitor to cutaneously sense cardiac electrical potential signals, particularly the P-wave and, to a lesser extent, the QRS interval signals indicating ventricular activity in the ECG waveforms. Additionally, the monitor recorder includes an ECG sensing circuit that measures raw cutaneous electrical signals and performs signal processing prior to outputting the processed signals for sampling and storage.

A method and system for R-R interval measurement of a user are disclosed. In a first aspect, the method comprises detecting an electrocardiogram (ECG) signal of the user. The method includes performing QRS peak detection on the ECG signal to obtain a low resolution peak and searching near the low resolution peak for a high resolution peak. The method includes calculating the R-R interval measurement based upon the high resolution peak. In a second aspect, a wireless sensor device comprises a processor and a memory device coupled to the processor, wherein the memory device includes an application that, when executed by the processor, causes the processor to carry out the steps of the method.

In one embodiment, an ambulatory encoding monitor recorder optimized for rescalable encoding and a method of use are provided. The monitor recorder includes a memory configured to store a plurality of codes and a plurality of electrocardiographic values associated with each of the codes; and a micro-processor configured to obtain electrocardiographic values during a sequence of temporal windows and to process the electrocardiographic values within each of the windows, the processing including: perform a mathematical operation on two of the electrocardiographic values; analyze a result of each of the mathematical operations; based on the analysis, adjust the plurality of the electrocardiographic values associated with each of the codes; encode each of the electrocardiography values within that window with one of the codes based on the adjusted plurality of the electrocardiographic values associated with that code; and write each of the codes into a sequence in the memory.

An electrocardiography monitor configured for self-optimizing ECG data compression is provided. ECG waveform characteristics are rarely identical in patients with cardiac disease making this innovation crucial for the long-term data storage and analysis of complex cardiac rhythm disorders. The monitor includes a memory and a micro-controller operable to execute under a micro-programmable control and configured to: obtain a series of electrode voltage values; select one or more of a plurality of compression algorithms for compressing the electrode voltage series; apply one or more of the selected compression algorithms to the electrode voltage series; evaluate a degree of compression of the electrode voltage series achieved using the application of the selected algorithms; apply one or more of the compression algorithms to the compressed electrode voltage series upon the degree of compression not meeting a predefined threshold; and store the compressed electrode voltage series within the memory.

An acoustic monitoring system has an acoustic front-end, a first signal path from the acoustic front-end directly to an audio transducer and a second signal path from the acoustic front-end to an acoustic data processor via an analog-to-digital converter. The acoustic front-end receives an acoustic sensor signal responsive to body sounds in a person. The audio transducer provides continuous audio of the body sounds. The acoustic data processor provides audio of the body sounds upon user demand.