Related Experiment Video
Updated: Oct 16, 2025
Signal Acquisition, Score Interpretation, and Economics of a Non-Invasive Point-of-Care Test for Coronary Artery Disease
Published on: August 9, 2024
Spectral analysis of heart sounds associated with coronary artery disease
Bjarke Skogstad Larsen1, Simon Winther2, Louise Nissen2
1Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
Insights
Coronary artery disease (CAD) patients exhibit distinct heart sound spectral differences compared to healthy individuals, particularly in diastolic segments. These findings suggest phonocardiography can offer new insights for CAD risk assessment.
Area of Science:
- Cardiology
- Biomedical Engineering
- Signal Processing
Background:
- Coronary artery disease (CAD) diagnosis relies on invasive or complex imaging methods.
- Phonocardiography (heart sound analysis) offers a non-invasive approach for cardiovascular assessment.
- Previous studies suggest spectral alterations in heart sounds of CAD patients, but detailed analysis is ongoing.
Purpose of the Study:
- To identify diagnostic spectral differences in heart sound recordings between patients with coronary artery disease (CAD) and healthy subjects.
- To investigate spectral characteristics of systole, diastole, and heart sound segments (S1, S2) in CAD.
- To evaluate the potential of phonocardiography for non-invasive CAD risk assessment.
Main Methods:
- Pooled heart sound recordings from 1146 patients (191 CAD, 955 Non-CAD).
- Welch's spectral density estimate applied to systole and diastole segments.
- Time-frequency spectral analysis of first (S1) and second (S2) heart sound segments.
- ANCOVA model used to assess statistical significance of diagnostic differences, controlling for age, gender, and BMI.
Main Results:
- CAD patients showed increased spectral energy in diastole and systole segments (20-120 Hz), with statistical significance in diastole.
- CAD patients exhibited decreased energy in mid-S1 and mid-S2 segments, with increased energy before and after valve sounds.
- Statistically significant differences were observed in time-frequency spectra of both S1 and S2 segments.
Conclusions:
- Findings support previous research on increased low-frequency energy in the diastole of CAD patients.
- Time-frequency components of S1 and S2 heart sounds contain significant, previously unrecognized information for CAD risk assessment.
- Further development of acoustic features based on these spectral differences could enhance non-invasive CAD detection.
Abstract:
Objective. The aim of this study was to find spectral differences of diagnostic interest in heart sound recordings of patients with coronary artery disease (CAD) and healthy subjects.Approach. Heart sound recordings from three studies were pooled, and patients with clear diagnostic outcomes (positive: CAD and negative: Non-CAD) were selected for further analysis. Recordings from 1146 patients (191 CAD and 955 Non-CAD) were analyzed for spectral differences between the two groups using Welch's spectral density estimate. Frequency spectra were estimated for systole and diastole segments, and time-frequency spectra were estimated for first (S1) and second (S2) heart sound segments. An ANCOVA model with terms for diagnosis, age, gender, and body mass index was used to evaluate statistical significance of the diagnosis term for each time-frequency component.Main results. Diastole and systole segments of CAD patients showed increased energy at frequencies 20-120 Hz; furthermore, this difference was statistically significant for the diastole. CAD patients showed decreased energy for the mid-S1 and mid-S2 segments and conversely increased energy before and after the valve sounds. Both S1 and S2 segments showed regions of statistically significant difference in the time-frequency spectra.Significance. Results from analysis of the diastole support findings of increased low-frequency energy from previous studies. Time-frequency components of S1 and S2 sounds showed that these two segments likely contain heretofore untapped information for risk assessment of CAD using phonocardiography; this should be considered in future works. Further development of features that build on these findings could lead to improved acoustic detection of CAD.
More Related Videos
04:40Identifying Coronary Artery Calcification on Non-gated Computed Tomography Scans
Published on: August 28, 2018
18:11A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis
Published on: December 28, 2012
Related Concept Videos
01:25Cardiovascular System Abnormal Findings II: Auscultation
Abnormal Heart Sounds
Gallops:
01:30Acute Coronary Syndrome III: Diagnostic Studies
01:15Heart Sounds
Auscultation is the process of listening to these internal body sounds using a stethoscope. The heart produces four types of sounds, but only two—S1 and S2—can usually be heard with a stethoscope.
S1, also known as the "lub" sound, is caused by the closure of atrioventricular (A-V)...
01:25Assessment of the Cardiovascular System IV: Auscultation
Normal Heart Sounds
S1 (First Heart Sound)-
S1 is made by the closure of the mitral and tricuspid valves (atrioventricular valves), marking the beginning of systole.
S2 (Second Heart Sound)-
S2 is made by the closure of the aortic and pulmonic valves (semilunar valves), marking the end of the systole.
01:22Rheumatic Heart Disease II: Clinical Manifestations and Diagnostic Studies
01:30Coronary Artery Disease III: Clinical Manifestations