Spectral Analysis of Heart Sounds Associated With Coronary Occlusions

Numerous studies based on the spectral analysis of diastolic sounds showed an increase in the high frequency portion of the spectrum for patients with coronary artery disease (CAD) compared with normal patients. The overall goal of this study is to detect the presence of coronary artery disease in patients using a noninvasive and inexpensive approach. A commercially available electronic stethoscope was used to record the diastolic heart sounds from patients diagnosed with or without CAD based on their coronary angiography examination. The Fast Fourier Transform, a widely used signal processing method, was then implemented on the diastolic segments. The power ratios of the energy above 130 Hz to the energy below 130 Hz were calculated for normal and abnormal patients and compared. Results furthermore confirmed that patients with CAD have more energy in the higher portion of their spectrum, resulting in higher power ratios than for normal patients (p < 0.05). This approach led to a sensitivity of 71%, a specificity of 83% and an overall accuracy of 73.3% using an optimal threshold ratio of 1.5. These results suggest that the proposed system could be used in clinics as part of standard physical examinations.