Cardiac compression wave measuring system and method

• US 4,989,611 A
• Filed: 08/19/1988
• Issued: 02/05/1991
• Est. Priority Date: 08/19/1988
• Status: Expired due to Fees

• Current Assignee: John M. Zanetti
• Original Assignee: Seismed Instruments Incorporated
• Inventors: Zanetti, John M., Salerno, David M.
• Primary Examiner(s): JAWORSKI, FRANCIS J
• Application Number:
  US07/234,031
• Time in Patent Office: 900 Days
• Field of Search: 128/668, 128/695, 128/696, 128/687, 128/714-715
• US Class Current: 600/508
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/6823 Trunk, e.g., chest, back, abdomen, hip
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R

Abstract

Seismic techniques and principles are used to provide a noninvasive method and apparatus for assessing selective cardiac performance by detecting compression waves generated by heart muscle function. An analog signal is generated by detecting compression waves in the range of 0.025 Hz to about 800 Hz at an exterior surface of a subject'"'"'s body by an accelerometer having a sensitivity of one (1) micro inch at one (1) Hz. Compression waves at frequencies above about 50 Hz are eliminated from the analog signal and then single full-cycle functions of the heart muscle are selected from a series of such cycles making up the analog signal. The selected single cycles may be averaged and waveform distortion may be removed from the averaged signal. Total energy level of the compression wave may be calculated and then the averaged signal may be displayed for visual analysis of a compression wave cycle representative of the muscle function of the heart.

Claims

1. Apparatus for the diagnostic display of motion signals characterizing the ventricular wall motion of a patient'"'"'s heart comprising:

compression wave detector means, coupled to said patient, responsive to cardiac induced compression waves at the surface of said patient, for generating motion signals indicative of said compression waves;

cardiac cycle selector means coupled to said patient for selecting normally conducted sinus beats of said patient'"'"'s heart and for generating a cardiac cycle signal during each of said normally conducted beats;

display means coupled to said cardiac cycle selector means and coupled to said detector means for diagnostic display of averaged data corresponding to said motion signals collected during said cardiac cycle signals.

2. The apparatus of claim 1 wherein said compression wave detector means comprises:

an accelerometer having a sensitivity of one microinch at one hertz.

3. The apparatus of claim 1 wherein said compression wave detector means comprises:

an accelerometer having a linear frequency response from 0.025 hertz to 800 hertz.

4. The apparatus of claim 1 wherein said cardiac cycle selector means comprises:

electrocardiographic detection means for determining the R-R intervals of patient heartbeats and for establishing a normal range of R-R intervals for said patients heart;

R wave to R wave interval selection means coupled to said electrocardiographic detection means for selecting beats of said patients heart within said normal range of R-R intervals and for generating a cardiac cycle signal indicating the occurrence of a normally conducted sinus beat of said patients heart.