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Noninvasive diagnostic system for coronary artery disease
| Details |
Inventors: Semmlow, John L.; Welkowitz, Walter; Kostis, John; Akay, Metin;
Assignee: Rutgers, The State University of New Jersey (New Brunswick, NJ)
Primary Examiner: Jaworski; Francis
Assistant Examiner: Manuel; George
Attorney, Agent or Firm: Oliff & Berridge
A method and system for non-invasively detecting Coronary Artery Disease. The method comprises analyzing the diastolic heart sounds detected from a patient's chest cavity during the diastolic portion of the heart cycle in order to identify a low level auditory component associated with turbulent blood flow in partially occluded coronary arteries. These diastolic heart sounds are modeled using advanced signal processing techniques such as Autoregressive (AR), Autoregressive Moving Averaging (ARMA) and Eigenvector methods, so that the presence of such an auditory component may be reliably indicated even under high noise conditions. The system includes an acoustic transducer, pulse sensor device, signal processor means and a diagnostic display. Additionally, the system includes a controller for automatically sequencing data collection, analysis and display stages, therefore requiring a minimum of operator interaction. The system further discloses a piezoelectric type low mass accelerometer for use as an acoustic transducer providing higher sensitivity at the high frequencies necessary for detecting coronary artery disease, specifically between 300 to 1200 Hz. In addition, the system discloses a method for automatically identifying and isolating a diastolic segment of a heart sound recording through a "window" placement technique. A window is placed relative to the second heart sound and various criteria are implemented to evaluate the recording for artifacts, i.e., data due to breath sounds, stomach growls, external ambient noise. |
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DETAILED DESCRIPTION Accordingly, the present invention has been developed to overcome the foregoing shortcomings by providing a system in which coronary artery disease may be detected both reliably and noninvasively.
It is therefore a primary object of this invention to provide reliable information to diagnose, or aid in a diagnosis of, coronary artery disease and to provide this information without discomfort or risk to the patient.
Another object of this invention is to provide reliable information which is more indicative of coronary artery disease, particularly in the early stages, than other low risk diagnostic methods.
Another object of this invention is to provide this information at low cost.
Yet another object of this invention is to provide this information without the need for highly trained operating personnel.
In carrying these objects forward, this invention provides a system for detecting heart sounds from a patient's chest cavity, parametrically modeling the detected heart sounds in order to identify various frequency components within the heart sounds, detecting the presence of an auditory component in the heart sounds model which is associated with turbulent blood flow in a partially occluded coronary artery, and presenting diagnostic information based on the detected presence of the auditory component.
According to another aspect of this invention, signal processing techniques are provided which isolate the heart sounds produced in the chest to a selected portion of the cardiac cycle during which coronary blood flow is maximum.
In accordance to another aspect of this invention, additional signal processing techniques are provided to perform a window placement technique relative to a second heart sound in order to isolate the heart sounds occurring during the diastolic segment of the cardiac cycle.
Additional signal processing techniques are provided whereby an evaluation for artifacts is performed on each diastolic segment, and a failure to meet one of several evaluation criteria will cause the record to be rejected
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Audio Signal Processing 
