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Updated: Jun 15, 2025

Semi-automated Optical Heartbeat Analysis of Small Hearts
Published on: September 16, 2009
Rapid detection and interpretation of heart murmurs using phonocardiograms, transfer learning and explainable
1Biophysics Department in Faculty of Medicine, Kahramanmaras Sutcu Imam University, 46100 Kahramanmaras, Turkey.
Insights
This study uses artificial intelligence to analyze heart sounds for early cardiovascular disease detection. The AI model effectively identifies murmurs and their severity, aiding faster clinical decisions.
Area of Science:
- Cardiology
- Artificial Intelligence
- Biomedical Signal Processing
Background:
- Cardiovascular disease is a leading cause of mortality.
- Early diagnosis of heart sounds, including murmurs, is crucial for prevention.
- Computer-aided systems can enhance murmur detection and decision-making.
Purpose of the Study:
- To develop and evaluate an AI model for detecting and classifying heart murmurs from phonocardiograms.
- To assess the model's ability to predict murmur presence, absence, and severity.
- To interpret the AI model's decisions using Explainable Artificial Intelligence (XAI).
Main Methods:
- Phonocardiogram signals were converted into Mel spectrograms.
- The OpenL3 network was used for transfer learning to classify the spectrograms.
- Murmur severity was classified using pitch level and Levine scale.
- Occlusion Sensitivity was employed as an XAI method for model interpretation.
Main Results:
- The AI model achieved impressive results in classifying murmurs without prior signal segmentation.
- The model successfully predicted the presence/absence and severity levels of murmurs.
- XAI analysis revealed the specific features the neural network utilized for decision-making.
Conclusions:
- AI, particularly using Mel spectrograms and transfer learning, shows significant potential for automated heart sound analysis.
- XAI methods are essential for understanding and trusting AI-driven diagnostic tools in cardiology.
- This approach can provide detailed insights into phonocardiogram features for improved cardiovascular diagnostics.
Abstract:
Cardiovascular disease, which remains one of the main causes of death, can be prevented by early diagnosis of heart sounds. Certain noisy signals, known as murmurs, may be present in heart sounds. On auscultation, the degree of murmur is closely related to the patient's clinical condition. Computer-aided decision-making systems can help doctors to detect murmurs and make faster decisions. The Mel spectrograms were generated from raw phonocardiograms and then presented to the OpenL3 network for transfer learning. In this way, the signals were classified to predict the presence or absence of murmurs and their level of severity. Pitch level (healthy, low, medium, high) and Levine scale (healthy, soft, loud) were used. The results obtained without prior segmentation are very impressive. The model used was then interpreted using an Explainable Artificial Intelligence (XAI) method, Occlusion Sensitivity. This approach shows that XAI methods are necessary to know the features used internally by the artificial neural network then to explain the automatic decision taken by the model. The averaged image of the occlusion sensitivity maps can give us either an overview or a precise detail per pixel of the features used. In the field of healthcare, particularly cardiology, for rapid diagnostic and preventive purposes, this work could provide more detail on the important features of the phonocardiogram.
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