Methods and apparatus for enhanced fiducial point determination and non-invasive hemodynamic parameter determination

Abstract

Methods and apparatus for utilizing multiple sources of physiologic data to enhance measurement robustness and accuracy. In one embodiment, phonocardiography or “heart sounds” data is used in combination with one or more other techniques (for example, impedance cardiography or ICG waveforms, and/or electrocardiography or ECG waveforms) to provide more accurate and robust physiological and/or hemodynamic assessment of living subjects. In one variant, the aforementioned methods and apparatus are used to improve ICG fiducial point (e.g., B, C and X point) detection and identification accuracy. Moreover, the new ICG fiducial points that may be clinically important may be identified using the disclosed methods and apparatus. In a further aspect, the invention discloses methods and apparatus for utilization of ICG and/or ECG waveform information to improve the identification and characterization of heart sounds (such as e.g., S1, S2, S3, or S4 heart 20 sounds), murmurs, and other such artifacts or phenomena.

We claim: 
     
         1 . A sensor apparatus for use in assessing cardiac function of a living subject, comprising:
 a substantially unitary base element;   a plurality of terminals, wherein the plurality of terminals are utilized in the communication of electrocardiographic and impedance cardiographic information of the living subject to a processing device;   an acoustic receptor device; and   a chamber configured to couple acoustic emissions from the living subject to the acoustic receptor device.   
     
     
         2 . The sensor apparatus of  claim 1 , wherein the substantially unitary base element and the plurality of terminals are of low cost thereby rendering the sensor apparatus disposable. 
     
     
         3 . The sensor apparatus of  claim 1 , wherein the acoustic receptor device comprises a piezoelectric device. 
     
     
         4 . The sensor apparatus of  claim 1 , wherein the acoustic receptor device comprises a piezoresistive device. 
     
     
         5 . The sensor apparatus of  claim 1 , further comprising one or more signal lines, wherein the one or more signal lines electrically couple the plurality of terminals and the acoustic receptor device to the processing device, and wherein the one or more signal lines are configured to simultaneously transmit electrocardiographic, impedance cardiographic, and acoustic information to the processing device. 
     
     
         6 . The sensor apparatus of  claim 1 , wherein the acoustic receptor device is removable and is configured to be received in a reception apparatus within the substantially unitary base element. 
     
     
         7 . The sensor apparatus of  claim 1 , wherein the acoustic receptor device is configured for wireless transmission of acoustic information. 
     
     
         8 . The sensor apparatus of  claim 1 , wherein the acoustic receptor device comprises an electromagnetic diaphragm. 
     
     
         9 . The sensor apparatus of  claim 8 , wherein the electromagnetic diaphragm further comprises: a substantially conductive coating disposed on a surface to form a coated surface; and a voltage-charged conductor located behind the coated surface. 
     
     
         10 . The sensor apparatus of  claim 1 , wherein the plurality of terminals includes a first terminal and a second terminal, wherein the first terminal is a different size than the second terminal. 
     
     
         11 . The sensor apparatus of  claim 1 , further comprising wireless means for transmitting data from the plurality of terminals and the acoustic sensor to the processing device. 
     
     
         12 . The sensor apparatus of  claim 11 , wherein the wireless means includes an RFID device. 
     
     
         13 . A disposable sensor apparatus for use in determining the cardiac function of a living subject, comprising:
 a patch-like substrate;   a first terminal and a second terminal, wherein the first terminal and second terminal are spaced a predetermined distance relative to each other;   an acoustic receptor device, wherein the acoustic receptor device, the first terminal, and the second terminal are disposed on the patch-like substrate; and   a chamber configured to couple acoustic emissions from the living subject to the acoustic receptor.   
     
     
         14 . The disposable sensor apparatus of  claim 13  wherein the acoustic receptor device comprises a piezoelectric device. 
     
     
         15 . The disposable sensor apparatus of  claim 13  wherein the acoustic receptor device comprises a piezoresistive device. 
     
     
         16 . The disposable sensor apparatus of  claim 13  wherein the acoustic receptor device is removable from the patch-like substrate. 
     
     
         17 . The disposable sensor apparatus of  claim 13  wherein the acoustic receptor device is configured to be received in a reception apparatus within the patch-like substrate. 
     
     
         18 . The disposable sensor apparatus of  claim 17  wherein the reception apparatus is configured to couple the acoustic receptor device to the chamber.