Abstract

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.

Other References

• David W. Mortara, Ph.D., Raymond E. Ideker, M.D., James J. Bailey, M.D.; Computerized Interpretation of the Electrocardiogram; Jun. 1984; Reference pp. 5-17 (James Bailey, M.D., Editor, Jun. 1984)
• Akay et al, "Analysis of Diastolic Heart Sounds Before and After Angioplasty", IEEE, EMBS 10th Int'l. Conf., Nov. 1988
• Akay et al, "Autoregressive Modeling of Diastolic Heart Sounds", IEEE, EMBS 10th Int'l. Conf. Nov. 1988
• Ortiz, M., "Acoustical Noninvasive Diagnosis of Coronary Artery Disease", Proc. of 13th Ann. NE. Bioeng. Conf., 1987
• Ortiz, M., "Non-Invasive Acoustical Diagnosis of Coronary Artery Disease", Thesis, May, 1987
• Ortiz et al, "Coronary Artery Disease: Noninvasive Diagnosis", 40th ACEMB Proceedings, Sep. 1987
• Vermarien et al, "The Recording of Heart Vibrations: A Problem of Vibration in Measurement . . . ", Med. & Bioeng. & Comp., Mar. 1984
• Semmlow et al, "Coronary Artery Disease--Correlates Between Diastolic Auditory . . . ", IEEE Trans. in BME, vol. 30, Feb. 1983
• Schwartz et al, "Improved Phonocardiogram System Based on Acoustic Impedance Matching", Am. J. Physiol., 1980
• Semmlow et al, "Non-Invasive Diagnosis of Coronary Artery Disease by Enhanced Coronary . . . ", IEEE Frontiers of Eng. in Health, 1982
• Kosugi, "Detection and Analysis of Cranial Bruit", IEEE Transactions on BME, vol. BME-34, No. 3, Mar. 1987
• Makhoul, "Linear Prediction: A Tutorial Review", Proceed. of the IEEE, vol. 63, No. 4, Apr. 1975
• Fischer et al, "Comparative Evaluation of Cardiac Microphones", IEEE EMBS 10th Int'l Conf., Nov. 198