Wireless electrode arrangement and method for patient monitoring via electrocardiography

Abstract

A wireless electrocardiogram (ECG) system is disclosed. The wireless ECG provides for recording potentials on the surface of a body. The wireless ECG includes a plurality of electrodes suitable for attachment to the surface of the body, a voltage measuring circuit for detecting a voltage between a reference voltage level and electrodes, an error detecting circuit, and a transmitting circuit for transmitting the detected voltage signal to a receiver. The disclosed system is robust in that it provides the capability of continuous monitoring of a subject while correcting for defects in an electrode, contact, presence of excessive noise or other developments in addition to providing the customary alarms in the event of disruptions.

1 . An apparatus for recording potentials on a body surface comprising:
 a plurality of electrodes attached to a conducting carrying surface, each electrode having at least a body contact for attachment to the body surface and at least a reference contact with a conducting component attached to the carrying surface, wherein the conducting component provides a common reference to one or more of the plurality of electrodes;   a voltage measuring circuit for detecting a voltage between a reference voltage level and the body contact;   an error detecting circuit; and   a transmitting circuit for transmitting a detected voltage level to a receiver over a wireless link.   
     
     
         2 . The apparatus of  claim 1 , wherein the voltage measuring circuit includes an amplifier to amplify one or more detected voltages. 
     
     
         3 . The apparatus of  claim 2 , wherein the voltage measuring circuit includes a filter to improve the signal-to-noise ratio of a detected voltage signal. 
     
     
         4 . The apparatus of  claim 2 , wherein the voltage measuring circuit detects and flags one or more of an open circuit and a short circuit. 
     
     
         5 . The apparatus of  claim 2 , wherein the transmitting circuit transmits one or more of a detected voltage signal, a plurality of parameters corresponding to a voltage signal, wherein the plurality of parameters are generated by predicting an expected signal and an error signal corresponding to a difference between the expected signal and a detected voltage signal. 
     
     
         6 . The apparatus of  claim 1 , wherein the common reference is provided by one or more of a conducting layer incorporated into the conducting carrying surface or a conducting element attached to a carrying surface to form the conducting carrying surface. 
     
     
         7 . The apparatus of  claim 3 , wherein the transmitting circuit transmits an error indicator in response to one or more of an open circuit, a short circuit, and an error detected by the error detecting circuit. 
     
     
         8 . The apparatus of  claim 7 , wherein the transmitting circuit transmits an indicator of a signal-to-noise ratio with the detected voltage signal. 
     
     
         9 . The apparatus of  claim 8 , wherein the signal-to-noise ratio is indicated by parameters corresponding to an error between a predicted voltage signal and a measured voltage signal such that the predicted voltage signal is determined from filter parameters based on a set of previously detected voltage levels. 
     
     
         10 . The apparatus of  claim 1 , further comprising a power supply having one or more of a battery, a transducer for providing electrical potential, and a receiver powered by external power. 
     
     
         11 . The apparatus of  claim 1 , further comprising a circuit printed on a flexible surface. 
     
     
         12 . The apparatus of  claim 1 , wherein the transmitting circuit comprises an RFID tag. 
     
     
         13 . The apparatus of  claim 1 , further comprising a receiver, wherein the receiver selects a signal detected by an electrode, from the plurality of electrodes, for use in synthesis of an ECG signal. 
     
     
         14 . The apparatus of  claim 13 , wherein the receiver polls a plurality of RFID tag based voltage sensors. 
     
     
         15 . The apparatus of  claim 15 , wherein the receiver selects a set of RFID tag based voltage sensors for synthesizing the ECG signal based on a signal-to-noise ratio. 
     
     
         16 . A method of collecting Electro-Cardiography Data comprising:
 monitoring a plurality of wireless electrodes, wherein each of the wireless electrodes may transmit over a wireless connection a signal corresponding to a voltage signal relative to a reference voltage;   detecting a first electrode with one or more of a low signal-to-noise ratio and error condition;   selecting a second electrode to supplement or replace the first electrode.   
     
     
         17 . The method of  claim 16 , further comprising polling a subset of the plurality of electrodes, wherein each electrode is connected to a mote. 
     
     
         18 . The method of  claim 16 , further comprising selecting the second electrode from a neighborhood of the first electrode, wherein the neighborhood is determined from the networking between motes connected to the first and second electrodes. 
     
     
         19 . An apparatus for collecting Electro-Cardiography Data comprising:
 means for monitoring a plurality of wireless electrodes, wherein each of the wireless electrodes may transmit over a wireless connection a signal corresponding to a voltage signal relative to a reference voltage;   means for detecting a first electrode with one or more of a low signal-to-noise ratio and error condition;   means for selecting a second electrode to supplement or replace the first electrode.   
     
     
         20 . The apparatus of  claim 19 , further comprising means for combining a signal from the second electrode to obtain a higher signal-to-noise ratio.